Q.Fill in the blank. During sexual reproduction, the process of syngamy results in the formation of a diploid cell called ______.

In external fertilisation, gametes are released into the external environment (typically water) where fusion of sperm and ovum occurs, rather than inside the female's body.

External fertilisation is a type of fertilisation seen in most aquatic organisms such as bony fishes, amphibians and many marine invertebrates (e.g., starfish). The male and female gametes are shed/released into the surrounding external medium (usually water), where fertilisation takes place outside the body of the female organism.

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Fertilisation is internal in sharks, so the answer is (B).

In internal fertilisation the male gametes are deposited inside the female's body, where syngamy occurs. Sharks (cartilaginous fishes) possess claspers in males for transferring sperm into the female, so fertilisation is internal.

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Fusion of a male and a female gamete (syngamy) produces a diploid zygote.

Syngamy is the fusion of two gametes (each haploid, carrying the 'n' number of chromosomes) — one male and one female — to form a single cell. Because each gamete contributes one full set of chromosomes, the resulting cell is diploid (2n). This diploid cell is called the zygote, and it is the first cell of the new individual, which …

Syngamy is the fusion of the male gamete with the egg cell to form the zygote; it is one of the two events that together make up double fertilization.

In angiosperms, the pollen tube delivers two male gametes into the embryo sac. One male gamete fuses with the egg (n + n -> 2n) - this fusion is called SYNGAMY, producing the diploid zygote that develops into the embryo. The second male gamete fuses with the two polar nuclei (n + n + n -> 3n) - this is TRIPLE FUSION, producing the triploid primary endosperm nucleus. Because these two fusion events occur together in the same embryo sac, the overall process is named DOUBLE FERTILIZATION (a term unique to angiosperms).

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