Q.Do you know for how many months pregnancy last in dogs, elephants, cats? Find out.

Showing the 12 most recent of 44 on this concept.

1. TG EAPCET 2026Set ap-2026-05-04-AN1 markMCQ
   Q.Match the following

   	Type of circulation		Examples
   A	Open type	I	Pisces
   B	Single circulation	II	Mammals
   C	Incomplete double circulation	III	Parazoans
   D	Double circulation	IV	Amphibians
   		V	Echinoderms

   The correct answer is (A) A – V, B – III, C – IV, D – II (B) A – II, B – IV, C – I, D – V (C) A – III, B – I, C – IV, D – V (D) A – V, B – I, C – IV, D – II

   ›Reveal solutionSolution

   Open type $\rightarrow$ Echinoderms (V), Single circulation $\rightarrow$ Pisces (I), Incomplete double $\rightarrow$ Amphibians (IV), Double $\rightarrow$ Mammals (II). That is A–V, B–I, C–IV, D–II, i.e. option (D).

   The concept first: two independent questions about any circulatory system

   Question 1 — is the blood always inside vessels?

   • Open circulation: the heart pumps blood into vessels that soon open into large body spaces (sinuses / haemocoel), where the tissues are bathed directly; the fluid then trickles back to the heart. Pressure is low and flow is slow. Found in arthropods (cockroach, prawn), most molluscs, and echinoderms — in a starfish the haemal system is open, and the associated water-vascular system likewise floods open channels.
   • Closed circulation: blood is confined to vessels throughout (arteries $\rightarrow$ capillaries $\rightarrow$ veins). Pressure is higher and distribution can be regulated precisely. Found in annelids, cephalopods and all vertebrates.

   Question 2 — how many times does the blood pass through the heart in one complete circuit?

   • Single circulation — once. In a fish, the two-chambered heart (one atrium + one ventricle) receives only deoxygenated blood, pumps it to the gills to be oxygenated, and the oxygenated blood then goes straight on to the body without returning to the heart first. So: heart $\rightarrow$ gills $\rightarrow$ body $\rightarrow$ heart. One pass.
   • Double circulation — twice: a pulmonary circuit (heart $\rightarrow$ lungs $\rightarrow$ heart) and a systemic circuit (heart $\rightarrow$ body $\rightarrow$ heart). It comes in two grades:
     • Incomplete double circulation — the heart has three chambers (two atria, one ventricle). Oxygenated blood from the lungs and deoxygenated blood from the body both enter that single ventricle and mix. This is the condition in amphibians (frog) and most reptiles.
     • Complete double circulation — the heart has four chambers (two atria, two ventricles), so the two blood streams are completely separated and never mix, giving highly efficient oxygen delivery. This is the condition in birds and mammals. …

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2. TG EAPCET 2026Set ap-2026-05-04-FN1 markMCQ
   Q.Characters related to ovule in Helianthes I. Inverted II. Curvature angle is $180^\circ$ III. Unitegmic IV. Micropyle lies close to funicle (A) I and II only (B) II and III only (C) I, II, III and IV (D) I, III and IV only

   ›Reveal solutionSolution

   The ovule of Helianthus (sunflower) is anatropous — it is inverted, with a $180^\circ$ curvature, unitegmic, and its micropyle lies close to the funicle. All four statements are correct, so the answer is (C).

   The question tests your knowledge of ovule types in angiosperms, specifically in Helianthus (sunflower), a member of the Asteraceae family. In botany, ovules are classified by their orientation and structure. The most common type in flowering plants — and the one found in Helianthus — is the anatropous ovule. Understanding what "anatropous" means is the key to evaluating each statement.

   An anatropous ovule is one that has undergone a complete 180° inversion during development. This inversion brings the micropyle (the opening through which the pollen tube enters) close to the funicle (the stalk attaching the ovule to the ovary wall). Such ovules are typically unitegmic (having a single integument) in many advanced families like Asteraceae.

   Let’s check each statement:

   1. Inverted — In an anatropous ovule, the body of the ovule is turned completely upside down relative to the funicle. The nucellus and embryo sac are oriented such that the micropyle points downward toward the placenta. This is true for Helianthus.

   2. Curvature angle is $180^\circ$ — The "curvature angle" refers to the angle between the funicle and the body of the ovule. In an anatropous ovule, this angle is exactly $180^\circ$, meaning the ovule is fully reflexed. This is a defining feature. …

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3. TG EAPCET 2026Set ap-2026-05-04-FN1 markMCQ
   Q.Choose the mismatched pair regarding cockroach (A) Spiracles – taenidia (B) Stigmata – peritremes (C) Trachea – intima (D) Ootheca – collaterial glands

   ›Reveal solutionSolution

   The question tests your knowledge of cockroach anatomy — specifically which structure is not correctly paired with its associated part. The mismatched pair is (D) Ootheca – collaterial glands, because the ootheca is formed by the colleterial glands, not the collaterial glands (a misspelling of the same term). All other pairs are correct.

   The key here is to recall the respiratory and reproductive systems of the cockroach. Each option pairs a structure with a feature or associated part. Let's go through them one by one.

   1. Spiracles – taenidia: Spiracles are the external openings of the tracheal system. Taenidia are the spiral thickenings inside the tracheae that prevent them from collapsing. This pairing is correct — taenidia are indeed found in the tracheae, which connect to spiracles.

   2. Stigmata – peritremes: Stigmata is another name for spiracles. Peritremes are the ring-like sclerites surrounding each spiracle. This is a correct match — peritremes are the structural borders of the stigmata.

   3. Trachea – intima: The trachea is lined by a cuticular layer called the intima, which is shed during moulting. This is correct — the intima is the inner lining of the tracheal tubes.

   4. Ootheca – collaterial glands: The ootheca is the egg case produced by the female cockroach. It is secreted by the colleterial glands (accessory reproductive glands). The term "collaterial glands" is a common misspelling or variant of "colleterial glands". However, in standard biology, the correct spelling is colleterial glands. Since the option uses "collaterial" (which is not the standard term), and more importantly, the pairing is actually correct in function — the ootheca is formed by the colleterial glands. But wait: the question asks for the mismatched pair. Let's re-examine carefully.

   Watch out

   A common trap: students often think "collaterial" is a typo and mark this as mismatched. But in many textbooks, "collaterial glands" is used interchangeably with "colleterial glands". The real mismatch here is subtle — the ootheca is indeed formed by these glands, so the pair is actually correct. That means the mismatched pair must be one of the others. …

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4. TG EAPCET 2026Set ap-2026-05-04-FN1 markMCQ
   Q.Study the following and identify the correct statements I. During inspiration thoracic spiracles are kept closed in cockroach II. In cockroach oenocytes of fat bodies contain symbiotic bacteria III. In cockroach stomodael valve lies between gizzard and mesenteron IV. In cockroach, alary muscles keep the blood in circulation (A) I, II (B) III, IV (C) I, IV (D) II, III

   ›Reveal solutionSolution

   The question tests four statements about cockroach anatomy and physiology. The correct statements are III (stomodael valve lies between gizzard and mesenteron) and IV (alary muscles keep blood in circulation), so the answer is option (B).

   The cockroach is a classic example in insect morphology, and these statements touch on respiration, fat body function, digestive tract structure, and circulation. Let’s examine each one carefully, because exam questions often mix a plausible-sounding wrong statement with a correct one.

   1. Statement I: “During inspiration thoracic spiracles are kept closed in cockroach.”

      Cockroaches have a tracheal system for gas exchange. Spiracles (openings on the thorax and abdomen) are controlled by valves. During inspiration (air intake), the abdominal spiracles typically open while the thoracic spiracles close, and during expiration the reverse happens. This is a coordinated mechanism to create a unidirectional airflow. So the statement is correct — thoracic spiracles are indeed kept closed during inspiration.

      But wait — many textbooks state that in cockroaches, the first pair of thoracic spiracles (on the prothorax) are always open, while the others are valved. However, the standard NCERT description says: during inspiration, the abdominal spiracles open and thoracic spiracles close. So this statement is true as per the syllabus.

   2. Statement II: “In cockroach oenocytes of fat bodies contain symbiotic bacteria.”

      Oenocytes are cells associated with the fat body in insects, and they are involved in lipid metabolism and cuticle formation. They do not contain symbiotic bacteria. Symbiotic bacteria in cockroaches are found in specialized cells called mycetocytes (or bacteriocytes) within the fat body, not in oenocytes. This is a common confusion — oenocytes and mycetocytes are different cell types. So statement II is false.

   3. Statement III: “In cockroach stomodael valve lies between gizzard and mesenteron.”

      The cockroach digestive tract has three regions: foregut (stomodeum), midgut (mesenteron), and hindgut (proctodeum). The stomodael valve (also called the cardiac valve or proventricular valve) is indeed located at the junction of the gizzard (part of foregut) and the mesenteron (midgut). It regulates the passage of food. This is a standard fact — statement III is correct.

   4. Statement IV: “In cockroach, alary muscles keep the blood in circulation.” …

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5. TG EAPCET 2026Set ap-2026-05-04-FN1 markMCQ
   Q.Consider the following statements Statement I: Both anal and sphincters are formed by smooth muscles in man Statement II: Renin converts the milk into curd (A) Both statement I and statement II are true (B) Both statement I and statement II are false (C) Statement I is true, but statement II is false (D) Statement I is false, but statement II is true

   ›Reveal solutionSolution

   Statement I is false because the external anal sphincter is made of skeletal muscle, not smooth muscle. Statement II is false because renin is an enzyme involved in blood pressure regulation, not milk curdling. Both statements are false.

   The key to this question is knowing the precise composition of the anal sphincters and the specific function of renin. Many students confuse the two anal sphincters (internal vs. external) and also mix up renin with rennin (also called chymosin), which is the enzyme that actually curdles milk. Let’s break each statement down.

   1. Statement I: "Both anal sphincters are formed by smooth muscles in man"

      The anal canal has two sphincters: the internal anal sphincter and the external anal sphincter. The internal anal sphincter is made of smooth muscle (involuntary, under autonomic control). The external anal sphincter, however, is made of skeletal muscle (voluntary, under somatic control). Because the external sphincter is not smooth muscle, the statement that both are formed by smooth muscle is false.

   2. Statement II: "Renin converts the milk into curd" …

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6. TG EAPCET 2026Set ap-2026-05-04-FN1 markMCQ
   Q.Consider the following statements Assertion (A): Placenta of human beings is described as haemochorial type Reason (R): Chorionic villi of the foetus are dipped in the blood pools of uterine wall (A) Both (A) and (R) are correct, (R) is the correct explanation for (A) (B) Both (A) and (R) are correct, (R) is not the correct explanation for (A) (C) (A) is correct, but (R) is not correct (D) (A) is not correct, but (R) is correct

   ›Reveal solutionSolution

   The human placenta is haemochorial because the foetal chorionic villi are directly bathed in maternal blood pools. Both statements are correct, and the Reason correctly explains the Assertion.

   The question tests your understanding of placental classification in humans. The term "haemochorial" literally means "blood" (haemo-) and "chorion" (the foetal membrane). The key idea is that in this type of placenta, the maternal blood comes into direct contact with the foetal chorionic tissue — there is no intervening layer of maternal endothelium or uterine epithelium. The Reason describes exactly that: the chorionic villi (foetal tissue) are dipped into pools of maternal blood. So the Reason is not just a true fact; it is the very definition of why we call it haemochorial.

   Let’s walk through the logic step by step.

   1. What does "haemochorial" mean?

      In placental mammals, the placenta is classified by how many layers separate maternal and foetal blood. In the haemochorial type, the maternal blood directly bathes the chorionic villi. The foetal chorion is in direct contact with maternal blood — hence "haemo" (blood) + "chorion". Humans, along with rodents and some other mammals, have this type.

   2. Check the Assertion (A):

      "Placenta of human beings is described as haemochorial type."

      This is correct. In human pregnancy, the trophoblast (outer layer of the blastocyst) erodes into the maternal endometrium, creating spaces called lacunae that fill with maternal blood. The chorionic villi project into these blood-filled spaces. So the assertion is true.

   3. Check the Reason (R):

      "Chorionic villi of the foetus are dipped in the blood pools of uterine wall." …

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7. TG EAPCET 2026Set ap-2026-05-05-FN1 markMCQ
   Q.Zygote is diploid in which life cycle? I. Haplotonic II. Diplontic III. Haplodiplontic IV. Diplohaplontic (A) I, II and III only (B) III and IV only (C) I, II, III and IV (D) I, II and IV only

   ›Reveal solutionSolution

   The zygote is formed by the fusion of two haploid gametes, making it inherently diploid ($2n$) in all sexually reproducing organisms, regardless of the specific life cycle pattern. Therefore, the zygote is diploid in haplotonic, diplontic, haplodiplontic, and diplohaplontic life cycles. The correct option is (C).

   Concept and Intuition

   Sexual reproduction fundamentally involves the fusion of two specialized cells called gametes. These gametes are typically haploid, meaning they contain a single set of chromosomes, denoted as $n$. When two haploid gametes fuse, their nuclei combine, resulting in a cell with two sets of chromosomes. This newly formed cell is called a zygote, and it is always diploid, denoted as $2n$.

   The type of life cycle (haplontic, diplontic, or haplodiplontic/alternation of generations) describes the relative prominence of the haploid and diploid phases in an organism's overall life history, and when meiosis occurs. However, the formation of the zygote itself is a consistent event: it is always the product of gamete fusion and is therefore always diploid. The subsequent development of the zygote and the timing of meiosis are what define the different life cycle types, not the ploidy of the zygote itself.

   Step-by-Step Explanation

   1. Understanding Zygote Formation:

      A zygote is the first diploid cell formed when two haploid gametes (sperm and egg in many organisms) fuse during fertilization. This fusion is a universal event in sexual reproduction.

   2. Ploidy of Gametes:

      Gametes are always haploid ($n$). This means they contain half the number of chromosomes found in the somatic (body) cells of the parent organism. This reduction in chromosome number occurs through a specialized cell division called meiosis.

   3. Determining Ploidy of the Zygote:

      When a haploid male gamete ($n$) fuses with a haploid female gamete ($n$), their genetic material combines. The resulting cell, the zygote, therefore contains two sets of chromosomes ($n + n = 2n$). This makes the zygote inherently diploid.

      $\text{Haploid Gamete} (n) + \text{Haploid Gamete} (n) \rightarrow \text{Diploid Zygote} (2n)$

   4. Applying to Different Life Cycles:

      Let's examine how this applies to the life cycles mentioned:

      • I. Haplotonic Life Cycle:

        In this life cycle (e.g., many algae, fungi), the dominant phase is haploid. The haploid organism produces haploid gametes by mitosis. These gametes fuse to form a diploid zygote ($2n$). Crucially, this zygote immediately undergoes meiosis to produce haploid spores, which then develop into new haploid organisms. Even though the diploid phase is very short-lived, the zygote itself is diploid.

      • II. Diplontic Life Cycle:

        In this life cycle (e.g., humans, most animals, some algae), the dominant phase is diploid. The diploid organism produces haploid gametes by meiosis. These gametes fuse to form a diploid zygote ($2n$), which then develops by mitosis into a new diploid organism. Here, the zygote is clearly diploid and initiates the diploid phase.

      • III. Haplodiplontic / IV. Diplohaplontic Life Cycle (Alternation of Generations): …

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8. TG EAPCET 2026Set ap-2026-05-05-FN1 markMCQ
   Q.Choose the tautonyms from the following I. Homo sapiens sapiens II. Axis axis III. Corvus splendens splendens IV. Naja naja (A) I, II only (B) I, II, III, IV (C) I, III, IV only (D) II, IV only

   ›Reveal solutionSolution

   Tautonyms are scientific names where the genus and specific epithet are identical, a practice allowed only in zoological nomenclature; thus, only Axis axis and Naja naja are tautonyms among the given options. The correct option is (D).

   The Art of Naming: Understanding Tautonyms

   In the fascinating world of biological classification, every known species gets a unique scientific name, a system designed to avoid confusion across languages and regions. This system, primarily developed by Carl Linnaeus, is called binomial nomenclature, meaning each species name has two parts: the genus name and the specific epithet (often informally called the species name). For example, in Homo sapiens, Homo is the genus and sapiens is the specific epithet.

   Sometimes, we need to distinguish between different populations within a species, leading to trinomial nomenclature for subspecies. Here, a third name, the subspecific epithet, is added. For instance, Homo sapiens sapiens refers to modern humans, where the third sapiens denotes the subspecies.

   Now, let's talk about tautonyms. A tautonym is a special case in zoological nomenclature where the genus name and the specific epithet are identical. It's like saying "Deer Deer" or "Cobra Cobra" in a formal scientific way. This practice is only permitted under the International Code of Zoological Nomenclature (ICZN). Interestingly, the International Code of Nomenclature for algae, fungi, and plants (ICNafp) forbids tautonyms.

   The intuition behind why they exist often comes from historical naming conventions, where a common name for an animal was simply duplicated when formalized into a scientific name.

   Step-by-Step Analysis

   Let's examine each given name to determine if it fits the definition of a tautonym. Remember, we're looking for identical genus and specific epithet.

   1. Understanding the Structure of Scientific Names

      • A binomial name consists of Genus + specific epithet (e.g., Canis lupus).
      • A trinomial name consists of Genus + specific epithet + subspecific epithet (e.g., Canis lupus familiaris).
      • A tautonym occurs when the Genus name is identical to the specific epithet (e.g., Gorilla gorilla).

   2. Analyzing I. Homo sapiens sapiens

      • Genus: Homo
      • Specific epithet: sapiens
      • Subspecific epithet: sapiens
      • Here, the specific epithet (sapiens) is identical to the subspecific epithet (sapiens). However, for a name to be a tautonym, the genus name must be identical to the specific epithet. In this case, Homo is not the same as sapiens.
      • Therefore, Homo sapiens sapiens is not a tautonym.
      Watch out

      A common pitfall is to confuse a repeated specific epithet in a trinomial (like sapiens sapiens) with a true tautonym, which requires the genus and specific epithet to be identical.

   3. Analyzing II. Axis axis

      • Genus: Axis …

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9. TG EAPCET 2026Set ap-2026-05-05-FN1 markMCQ
   Q.Consider the following statements Statement I: Radially symmetrical animals are generally sluggish Statement II: In human body, kidneys are retroperitoneal organs The correct answer is Options : (A) Both statement I and statement II are true (B) Both statements I and statement II are false (C) Statement I is true, but statement II is false (D) Statement I is false, but statement II is true

   ›Reveal solutionSolution

   Radially symmetrical animals are typically slow-moving or sessile, and kidneys in the human body are indeed located behind the peritoneum. Therefore, both statements are true.

   The question asks us to evaluate two independent biological statements. We need to determine the truthfulness of each statement based on established biological principles.

   Concept and Intuition

   For Statement I (Radial Symmetry):

   Symmetry in animals refers to the arrangement of body parts around a central axis or plane. Radial symmetry means that the body can be divided into two identical halves by any plane passing through the central axis. This body plan is often associated with animals that are sessile (attached to a substrate) or planktonic (drifting), as it allows them to detect food or threats from any direction. Such animals typically do not exhibit fast, directed movement.

   For Statement II (Retroperitoneal Organs):

   The peritoneum is a serous membrane that lines the abdominal cavity and covers most of the abdominal organs. Organs can be classified based on their relationship to this membrane:

   • Intraperitoneal organs are suspended within the peritoneal cavity by mesenteries and are almost completely covered by visceral peritoneum.
   • Retroperitoneal organs are located behind the peritoneum, meaning they are covered by peritoneum only on their anterior (front) surface. They are not suspended by mesenteries.

   Let's analyze each statement:

   1. Analyzing Statement I: Radially symmetrical animals are generally sluggish.
      • Animals with radial symmetry, such as jellyfish (Cnidaria) and adult starfish (Echinodermata), typically lack a distinct head and tail, which are features associated with directed, active movement.
      • Their body plan allows them to interact with their environment from all sides. This is advantageous for sessile organisms (like sea anemones) that filter feed, or for slow-moving or drifting organisms (like jellyfish) that capture prey as it comes into contact with their tentacles. …

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10. TG EAPCET 2026Set ap-2026-05-05-FN1 markMCQ
    Q.Choose the mismatched pair regarding cockroach (A) Alary muscles – blood circulation (B) Malpighian tubules - excretion (C) Dorso ventral muscles - respiration (D) Anal styles – female

    ›Reveal solutionSolution

    The question asks to identify the mismatched pair regarding cockroach anatomy and function. Anal styles are characteristic structures found only in male cockroaches, not females. Therefore, the pair "Anal styles – female" is mismatched.

    The question tests your knowledge of the specific anatomical structures and their functions in a cockroach, particularly focusing on distinguishing features and physiological roles. To identify the mismatched pair, we need to evaluate each option based on established biological facts about cockroaches.

    1. Analyze option (A) Alary muscles – blood circulation:

       • Alary muscles are fan-shaped muscles located in the dorsal part of the cockroach's body, associated with the dorsal diaphragm.
       • Their rhythmic contractions help in the circulation of hemolymph (insect blood) within the hemocoel by assisting the pumping action of the tubular heart. They create pressure gradients that facilitate the movement of hemolymph.
       • This pair is matched.

    2. Analyze option (B) Malpighian tubules - excretion:

       • Malpighian tubules are the primary excretory and osmoregulatory organs in insects, including cockroaches.
       • They are fine, yellow, filamentous tubules that absorb metabolic wastes, salts, and water from the hemolymph and discharge them into the hindgut for elimination.
       • This pair is matched.

    3. Analyze option (C) Dorso ventral muscles - respiration:

       • Dorso-ventral muscles (also known as tergo-sternal muscles) connect the dorsal (tergum) and ventral (sternum) plates of the abdominal segments.
       • Their contraction and relaxation cause changes in the volume of the abdomen. These abdominal pumping movements create pressure differences within the tracheal system, which aids in the movement of air (ventilation) into and out of the spiracles and tracheae, thereby facilitating respiration.
       • While the primary respiratory structures are spiracles and the tracheal system, these muscles play a role in active ventilation, especially during increased metabolic activity. …

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11. TG EAPCET 2026Set ap-2026-05-05-FN1 markMCQ
    Q.Consider the following statements Statement I: Main region of digestion in stomach in man is pyloric part Statement II: Lipase of bile juice play an important role in digestion of fats The correct answer is (A) Both statement I and statement II are true (B) Both statement I and statement II are false (C) Statement I is true, but statement II is false (D) Statement I is false, but statement II is true

    ›Reveal solutionSolution

    The question tests two separate biology facts: the stomach’s main digestive region and the source of lipase. Statement I is false (the pyloric part is mainly for chyme passage, not digestion); Statement II is false (bile has no lipase; pancreatic lipase does the work). So both are false.

    Concept & Intuition

    This is a classic “two-statement true/false” question from human physiology. You need to recall two distinct ideas:

    • The stomach has different regions (cardiac, fundic, body, pyloric). The main site of chemical digestion in the stomach is the body (or fundus), where gastric glands secrete pepsinogen and HCl. The pyloric part is mostly a muscular funnel that regulates chyme release into the duodenum — it does very little digestion.
    • Bile is produced by the liver, stored in the gallbladder, and released into the small intestine. It contains bile salts (for fat emulsification) but no enzymes. Lipase, the fat-digesting enzyme, comes from the pancreas (pancreatic lipase) and, to a lesser extent, from the stomach (gastric lipase). Bile juice itself has no lipase.

    Thus both statements are incorrect.

    Step-by-step reasoning

    1. Evaluate Statement I: “Main region of digestion in stomach in man is pyloric part”

       • The stomach is divided into cardia, fundus, body, and pyloric part.
       • The body (and fundus) contains chief cells (secrete pepsinogen) and parietal cells (secrete HCl). This is where protein digestion begins.
       • The pyloric part (pyloric antrum and pyloric canal) secretes mucus and the hormone gastrin, but its primary role is mechanical — mixing and pushing chyme into the duodenum.
       • Therefore, the pyloric part is not the main region of digestion; the body is.
       • Conclusion: Statement I is false.

    2. Evaluate Statement II: “Lipase of bile juice play an important role in digestion of fats”

       • Bile juice contains water, bile salts, bilirubin, cholesterol, and electrolytes — but no digestive enzymes. …

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12. TG EAPCET 2026Set ap-2026-05-05-FN1 markMCQ
    Q.Consider the following Assertion (A): Colostrum is absolutely essential for the newly born baby Reason (R): It contains several antibodies that protect the new born from initial sources of infections (A) Both (A) and (R) are correct, (R) is the correct explanation of (A) (B) Both (A) and (R) are correct, (R) is not the correct explanation of (A) (C) (A) is correct, but (R) is not correct (D) (A) is not correct, but (R) is correct

    ›Reveal solutionSolution

    Colostrum is essential because it provides passive immunity via maternal antibodies. Both the assertion and reason are true, and the reason correctly explains the assertion — so option (A) is correct.

    The question tests your understanding of colostrum and its role in passive immunity — a key concept in human physiology and immunology. Let’s break it down.

    1. What is colostrum?

       Colostrum is the first milk secreted by the mother immediately after childbirth, typically for the first few days. It is thick, yellowish, and rich in nutrients, but its most critical component is antibodies (immunoglobulins), especially IgA.

    2. Why is it essential for a newborn?

       A newborn’s immune system is immature and cannot produce its own antibodies effectively. The antibodies in colostrum are absorbed directly into the baby’s bloodstream through the gut, providing passive immunity — immediate protection against pathogens the mother has encountered. This is vital because the baby is suddenly exposed to a world full of microbes after the sterile environment of the womb.

    3. Does the reason correctly explain the assertion?

       The assertion says colostrum is “absolutely essential” — and it is, because without those maternal antibodies, the newborn would be highly vulnerable to infections. The reason states that colostrum contains antibodies that protect against initial infections. This is the direct mechanism by which colostrum provides that essential protection. So the reason is not just true — it is the specific explanation for why the assertion holds. …

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