If a sample of DNA contains 40% guanine (G), what percentage of the DNA molecule contains cytosine (C)?

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

~fourth largest plate ~includes parts of the indian and atlantic oceans ~subducts below the eurasian plate on the west side ~ the arabian and somali plates form boundaries with it what is the name of the tectonic plate described above? a) african plate b) eurasian plate c) north american plate d) indo- australian plate

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.