Skip to content
Evaluation · Q12

Q.Identify the A, B, C and D in the given table
Interaction / Effects on species X / Effects on species Y
Mutualism — A (+)
B (+) (-)
Competition (-) — C
D (-) 0
[Answer choices, as printed in the source, whose cells could not be reliably realigned to the A/B/C/D table above:]

a) (+) Parasitism / (-) / — / Amensalism
b) (-) / Mutalism / (+) / Competition
c) (+) Competition /
(0) / Mutalism / —
d)
(0) / Amensalism / (+) / Parasitism
Tamil Nadu DgeTextbookSubjectiveImportance★★★★★
15% · 12/82 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Step 1. Solve for A (the Mutualism row). Mutualism is defined as an interaction in which BOTH species benefit, i.e. the sign pattern is (+, +). Since the printed effect on species Y is already '(+)', the missing effect on species X, labelled 'A', must also be '(+)'.

Step 2. Solve for B. Row B's printed effects are '(+)' on X and '(-)' on Y — one species benefits while the other is harmed. Among the interaction names offered across the answer choices (Parasitism, Mutualism, Competition, Amensalism), the one matching a (+, -) sign pattern is Parasitism, where the parasite gains at the host's expense. So B = Parasitism.

Step 3. Solve for C (the Competition row). Competition is defined by BOTH species being harmed, i.e. (-, -). Since the printed effect on X is already '(-)', the missing effect on Y, labelled 'C', must also be '(-)'.

Step 4. Solve for D. Row D's printed effects are '(-)' on X and '0' on Y — one species is harmed while the other is unaffected. This (-, 0) sign pattern is the definition of Amensalism, so D = Amensalism. …

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.