CBSE Class 10 Science 2017 · Paper 31/2/3 · Question 11

The two types of mammalian gametes are the male gamete, the sperm, and the female gamete, the egg (ovum). Differences: the sperm is small and motile — it swims with its tail — whereas the egg is much larger and non-motile; the egg contains a store of food for the early embryo, while the sperm has almost none; sperms are produced in very large numbers by the testes, whereas the ovaries release far fewer eggs (in humans, usually one a month). They are involved in sexual reproduction. Advantage: sexual reproduction combines DNA from two different individuals, so the offspring show new combinations of variations; this variation makes it more likely that some individuals of the species survive when the environment changes.