What is homeostasis and why is it essential for living things?

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex