Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?

a. fluffing decreases the amount of heat loss by conduction when the bird makes contact with cold objects in its environment
b. fluffing creates a pocket of air near the bird that acts as insulation
c. fluffing decreases the surface-area-to-volume ratio, thus decreasing the amount of heat loss to the environment
d. fluffing feathers results in less cooling by radiation because feathers emit less infrared radiation than other tissues do

18. determine whether each stateme blank space given. ach statement is true (t) or false (f). place your answer in the 8. when a cell is put into an isotonic solution, individual wat put into an isotonic solution, individual water molecules cannot move back and forth across the cell membrane. d. when a cell is put into a hypertonic solution, there is a net movement of water molecules across the cell membrane into the cell. c. when a cell is put into a hypotonic solution, there is a net movement of water molecules across the cell membrane out of the cell. d. the movement of any solvent across a semi-permeable membrane is called osmosis. e. carrier proteins have the ability to change shape and physically move molecules across the cell membrane. f. in facilitated diffusion, the concentration of the molecules to be moved across the cell membrane is higher inside the cell.