A student makes a model of the sun-Earth system by swinging a ball around her head. Using this model, the student is trying to explain how Earth stays on a path around the sun. The student explains that this path is the result of —

Which of the following statements regarding anfinsen's denaturing experiments with ribonuclease a (rnase a) are valid? exposing the denatured protein to air oxidation and then dialysis to remove urea restored the protein to its original functionality. removing urea by dialysis and then allowing air oxidation of the denatured protein restored the protein to its original functionality. denaturing the protein with both urea and β-mercaptoethanol yielded an inactive protein. anfinsen concluded that protein folding is determined by its primary sequence.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

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.