Biology help please! (:

Which of the following best explains ways in which fish and mammals differ?

A. Fish are invertebrates and have scales and paired fins, while mammals are vertebrates and have fur or hair.
B. Fish are ectothermic and lay eggs to reproduce, while mammals are endothermic and give live birth to offspring.
C. Fish are endothermic and have gills, while mammals are ectothermic and have lungs.
D. Fish have streamlined bodies and three-chambered hearts, while mammals are bipedal and have four-chambered hearts.

I know that its either A or B, im pretty sure.

Thanks for the help! (:

It is A. Some fish give live birth so it cannot be B.

Its definitely A. I done a module on fish and humans gases exchange system in AS biology. And the main difference between them is fish get their blood oxygenated at their gills and mammals at their lungs

Hope this helped