Which best describes the structure of the molecules that make up proteins? A. Carboxyl group + amino group + side chain
B. Carbon + hydrogen + oxygen
C. Phosphate + sugar ring + nucleotide base
D. Hemoglobin + oxygen + iron

Which of the following describes a negative feedback loop? when the heart rate is too high, the body sends hormones that continually increase the heart rate higher. when a pregnant woman is in labor, the body sends hormones that increase the intensity of contractions, which then increases the secretion of the same hormones. when blood sugar is too low, the body sends hormones that raise blood sugar until it reaches a typical level and hormone secretion slows. when a person is jogging, the body sends hormones that continually decrease the rate of oxygen supply to the legs.

Anne, an intern in a microbiology lab, was observing the characteristics of various specimens of protists. match each specimen to the category of protist to which it belongs.

The first amino acid of a new polypeptide chain is