Comparable segments of the mitochondrial dna sequences of two similar species are shown below. this segment of dna mutates at a rate of one base pair per 33 million years. based on these dna sequences, how long ago did the two species diverge from a common ancestor?

species a mtdna sequence: tacaagatac
species b mtdna sequence: tacgcgtaac

a. 99 million years ago
b. 33 million years ago
c. 66 million years ago
d. 132 million years ago

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.