Which of these describes one way that the human nervous system maintains a constant body temperature when the external temperature is cold? a) the nervous system increases perspiration. b) the nervous system causes digestion to speed up. c) the nervous system causes blood vessels to constrict. d) the nervous system triggers the fight-or-flight response.

During the process of meiosis, special cells called gametes are formed. gametes only have half the number of chromosomes that the other cells in the body have. what form of reproduction do organisms that produce gametes use?

Bisphenol a (often called bpa) is a chemical found in products that people use every day, from water bottles to food containers to children's toys. unfortunately, bpa leaches out of its many products and makes its way into our bodies. what are the health effects of bpa exposure? ongoing research is finding that elevated exposure to bpa can affect a wide variety of developmental and physiological processes, but one of the first studies of bpa's health effects came about because of a simple mistake in the lab. at a laboratory at case western reserve university in 1998, geneticist patricia hunt was making a routine check of her female lab mice. as she extracted and examined developing eggs from the ovaries, she began to wonder what had gone wrong. she noticed that many of the eggs showed problems with their chromosomes, and some had irregular amounts of genetic material, which can lead to miscarriages and birth defects in mammals. she learned that a lab assistant had mistakenly washed the plastic mouse cages and water bottles with a harsh soap, releasing bpa from the plastic. knowing that bpa is an endocrine disruptor, a chemical that can enter organisms and mimic hormones, hunt set out to discover whether it had adversely affected her mice.

How is the carbon cycle related to global warming ?