Earthworms and sponges are animals.

is the vital link that ensures continuity between one generation to the next.

 In oviparous animals like reptiles and birds, the fertilised egg is covered by a shell and laid in a safe place.

Gametogenesis and gamete transfer are events.

cycle occurs in non-primate mammals like cows and dogs.

are the motile microscopic structures produced by many algal species.

The offspring of animals are vulnerable to predators.