Question

In which of the following fertilization occurs externally in water?

• A. Hydra
• B. Frog
• C. Both of the above
• D. None of the above

Answer 1

Answer: (C)

Both of the above

A complex series of developmental events in the gonads of the parents produces sperm and eggs (gametes), the highly specialized cell types, that unite during fertilization. The main function of fertilization is the combining of haploid sets of chromosomes from two individuals into a single diploid cell, the zygote. Contact of the sperm with the egg's surface also initiates metabolic reactions within the egg, that trigger the onset of embryonic development, thus, "activating" the egg. Lower aquatic animals like Cnidaria - example Hydra, fishes, and amphibia show external fertilization, while higher animal forms like birds and mammals show internal fertilization.

So, the correct answer is option C