A track runner starts running at 4 m/s. Twenty five seconds later, the runner has a velocity of 10 m/s. What is the acceleration of the runner? Is this positive or negative acceleration?

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.