Facilitated diffusion is a form of passive transport utilizing membrane proteins. When is facilitated diffusion used rather than diffusion? A) Facilitated diffusion is used when energy is required for transport.
B) Facilitated diffusion is used when concentrations must be more closely controlled.
C) Facilitated diffusion is used when molecules need to move more quickly across the cell membrane.
D) Facilitated diffusion is used when molecules cannot diffuse through the cell membrane , because the lipid bilayer repels the polar molecule.

What are some aquatic organisms that live in cold water temperatures?

Hormones are chemical molecules produced by endocrine glands. one such endocrine gland is the thyroid gland, which synthesizes the thyroid hormone, which in turn affects the heart muscles. which two statements describe the probable reason for the function of the hormone? the cells in the heart have specific receptors that allow for the intake of hormones. the heart and the endocrine glands have the exact same types of cells. all cells make the same types of hormones. thyroid hormones show their effect on the heart by means of specialized cells. thyroid cells and cardiac cells have different dna.

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?