Ok here is the next one. The answer selected was just accidentally tapped so ignore it lol.

Consider the skeleton. which skeletal system is represented by the shaded portion of the skeleton? spongy skeleton compact skeleton axial skeleton appendicular skeleton

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.

Which of the following requires the use of energy and the of transport proteins to move a molecule across a cell membrane?