The following are examples of oviparous animals except

1. Analyze the question We are asked to find the animal that is NOT oviparous. So we need to know what "oviparous" means.

2. Explain the concept

• Oviparous animals lay eggs, and the embryo develops outside the mother's body, inside the egg (e.g. birds, most reptiles, most fish, amphibians, insects).
• Viviparous animals give birth to live young, and the embryo develops inside the mother's body, nourished through a placenta (e.g. most mammals).
• Ovoviviparous animals keep the eggs inside the body until they hatch (e.g. some sharks and some snakes).

3. Solution: check each option

• A. Crocodile is a reptile and lays eggs, so it is oviparous.
• B. Dove is a bird and lays eggs, so it is oviparous.
• C. Rat is a mammal. The embryo develops in the uterus and the young are born alive, so it is viviparous, not oviparous.
• D. Tilapia is a bony fish that lays eggs (and the female even incubates them in her mouth), so it is oviparous.

4. Answer The rat is the exception, so the answer is C.

5. Exam tip Remember: Mammals = live birth (viviparous), with the exceptions of egg-laying mammals like the platypus and echidna. Birds, reptiles, most fish and amphibians = lay eggs (oviparous). Memory trick: OVI = egg (think "ovum"), so oviparous = egg-laying.