Apacemaker adjusts the heart rate to correspond to the body's what

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.

Select the correct answer from each drop-down menu. the lac operon in e.coli regulates genes that code for enzymes required for breakdown of lactose. the lac operon is operon that is activated in the presence of .

How far down have geologists drilled holes ? (science) a: 3.8 km b: 12 km c: 100 m d: 1200 km