Concept:The animals differ in how strongly they need water to reproduce successfully.
Explanation:The fish labelled IV depends completely on water because fertilisation and egg development occur in water.
The toad labelled III still depends on water for laying eggs and for its tadpoles to develop.
The alligator labelled II lays eggs in a mud nest, so it is less dependent on water for reproduction.
The rabbit labelled I gives birth in a burrow and has no aquatic requirement.
So the order of decreasing dependence on aquatic conditions for reproduction is fish, toad, alligator, rabbit.
Answer:B. IV, III, II and I.
