Proteins carry out much of the biochemistry of life, including dna replication, but dna stores the information needed to build correct proteins. early life forms would have needed both proteins and dna, but neither can exist without the other. the rna world hypothesis is an appealing solution to this problem, because it states that

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.