The body uses two types of digestion, mechanical and chemical, to break down food into small components. Mechanical digestion physically breaks down pieces of food, whereas chemical digestion breaks down food on the molecular level. Why must food molecules become chemically broken down into smaller component molecules by the body?

Photosynthesis uses co2 and cellular respiration produces co2. we call the point when the two processes are in balance--when there is no net production of co2--the compensation point. how might you limit one of the processes in order to achieve a compensation point?

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.

Hairs that clean dirt out of the air in your nasal passages are called: a. sinus b. trachea c. cilia d. mucus