Which statement is true of diffusion?

a: molecules move from areas of high concentration to areas of low concentration.

b: diffusion requires energy input from the cell.

c: only water can diffuse across a cell membrane.

d: diffusion is only important for animal cells.

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