Which of the following is true about the flow of energy within ecosystems? A.
Energy flows both ways between living systems and the physical environment.
B.
Energy flows from the physical environment into living systems only.
C.
Energy does not flow between living systems and the physical environment.
D.
Energy flows from living systems into the physical environment only.

When a person is exercising the body needs to deliver increased amounts of oxygen to the muscles which component of blood ensures that the muscles will receive it

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.

Vessels draining the myocardium of the heart, open primarily ,into which chamber?