Huntington disease can strike at an earlier age and bring about a more rapid degeneration and death in successive generations within a family. this phenomenon can be explained by which mechanism?
a. presence of a transposable element in the gene.
b. chronic exposure to mutagens in the environment.
c. expansion of a trinucleotide repeat in the coding sequence of the gene.
d. presence of an extra chromosome in the germ line.
e. absence of a gene product that is involved in dna repair.

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.