Which pair of statements correctly describes a way that the chromatin contributes to gene expression?

answer; /// i do believe its (heredity); good luck

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

looks like the answer is     c     to me!