Which organ system makes blood?
a. digestive system
b. skeletal system
c. circulatory system
d. nervous system user: if you see a multicellular organism whose cell walls lack cellulose, it belongs to which kingdom?
a. archaebacteria
b. plantae
c. fungi
d. animalia

Which phrase is the best summary of the model shown? a. the transfer of the sun's energy through trophic levels b. a series of aerobic and anaerobic reactions c. a transformation of light energy into chemical energy d. the breakdown of food molecules

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.

Kinases add - groups to other enzymes. this activities some enzyme while inhibiting other