Answer:
C
Explanation:
1. Ectotherm: Ectotherm are cold-blooded animall whose regulation of body temperature depends on external sources, such as sunlight and many other environmental factors.
2. They do not maintain their body temperature by self, so their body temperature changes externally.
3. They are also known as cold blooded animals.
3.They invests little energy in temperature regulation.
4. Example of ectotherms: include the fishes, amphibians, reptiles, and invertebrates.