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
For starters, humans have feelings and cells. If we get hurt we can feel things such as pain unlike a tent. If you hit a tent there is nothing it feels because it has no feelings. We have cells all through our body and rocks don't. They are made of other stuff but not cells.
The energy before and after a process must be the same.