There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared: a. ancestral character of the reptiles and mamma
b. derived character of mammals, but only if cynodonts are reclassitied as mammals
c. derived character of mammals, even if cynodonts continue to be classified as reptiles
d. ancestral character of the mammal clade but not the reptiles clade.

What is the significance of the protein-lined pits? a. protein attracts other proteins needed for atp synthesis within the cell. b. protein-lined pits are able to transport one molecule at a time down the concentration gradient within the cell. c. the polarity of proteins allows other polar molecules to attach and be transported in the cell by transport channels. d. receptors within the pits allow ligands to fuse and be transported into the cell by endocytosis.