Autographs are organisms that make their own food/energy. The only example I can think of (and the only one I think exists) is plants. They make glucose from the sun and other stuff
Heterotrophs are organisms that needs to get its energy from other sources. You and me are heterotrophs (well unless you are a plant lol). We have to eat food to get energy to survive.
Hope this helped!!!
Answer:
Option A, most closely related to mammals
Explanation:
Insects like arthropods and molluscs have an open circulatory system and thus do have a distinguishable heart. Fish has two chambered heart. Reptiles have three chambered heart. Amphibians too have a three chambered heart.
All mammals and fish have four chambered heart. The right and left sides of the chambers have restricted entry and hence remain intact from each other
Hence, option A is correct
They are changed because of the environments changing
