What is the ring of atoms called which is present in iron in our blood and makes the color of blood red?

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.

What is used as a template during replication? a- mrna b- trna c- rrna d- dna

The krebs cycle is also known as the calvin cycle pyruvic acid cycle carbon - oxygen cycle citric acid cycle