An electron a. can gain energy and move into the orbital of a shell closer to the nucleus
b. can lose energy and fall toward the orbital of a shell farther from the nucleus
c. can leave its home orbital and take up residence in the orbital of another atom
d. can move to a shell farther away frim its nucleus by giving up a photon of light
e. all of above

true                                                                                                       true true true true true true

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

bacterium is not correct