AIIMS 2013 Biology Question Paper for free online practice with solutions

The earthworms are bisexual or hermaphrodite or monoecious and protandrous. The self-fertilization is not possible in the earthworm because of the relative position of openings of male and female reproductive organs, hence cross fertilization takes place. During mating, two worms attach themselves with their ventral surfaces and become opposed to each other in opposite direction to exchange packets of sperms called spermatophores. . Mature sperm and egg cells and nutritive fluid are deposited in cocoons, produced by the gland cells of clitellum. The ova (eggs) are fertilized by . the sperm cells within the cocoon which then slips off the worm and is deposited in or on the soil. The cocoon holds the worm embryos. After about 3 weeks, each cocoon produces two to twenty baby worms with an average of four.