Which of the following are true about negative feedback mechanisms? Check all that apply. They control the muscular contractions during childbirth. They make internal changes to achieve a set point. They let you know you need to put on a jacket in cold weather. They help adjust the external environment.

The cluster of developing cells from conception until birth is called an

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.

Abeaker of water was heated and then placed on a bench in the laboratory. the water cooled until it was the same temperature as the air in the laboratory. which of these explains the mechanism by which the water cooled? a. heat energy was transferred from the water to the air. b. water molecules from the water formed warm water currents. c. the water molecules absorbed energy from the molecules in the air. d. the water released radiation until it contained no heat energy.