Microbiologists have announced the discovery of over 30 new species of bacteria that thrive between the teeth and gums of humans. The bacteria could not be grown in the researcher's laboratories, nor were any of them ever observed via any kind of microscopy. If they couldn't culture them or see them, how could the researchers know they had discovered new species? If they couldn't examine the cells for the presence of a nucleus, how did they determine that the organisms were prokaryotes and not eukaryotes?

Which of the following is an advantage of solar energy?

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.

Which statement about the pancreas is not true? a. it is an endocrine organ in the abdomen. b. it release chemicals into the digestive system. c. it releases insulin to increase glucose levels. d. it release hormones into the bloodstream.