In the human body, each hormone is regulated by certain genes. These genes are turned on at times and turned off at other times. Which best explains this process? Genes are directly regulated by hormones found in the integumentary system.

a. Genes are regulated by hormones secreted by the endocrine system.

b. The regulation of genes is only affected by external factors.

c. The regulation of genes is directly controlled by the nervous system.

Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? a. the chlorofluorocarbons act like ultraviolet radiation causing large amount of ozone to be produced. b. the chlorine from the chlorofluorocarbons reacts with free molecules of oxygen causing a stop in ozone production c. free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone. d. chlorofluorocarbons absorb ultraviolet radiation, preventing the formation of ozone select the best answer from the choices provided

Which heredity condition causes a buildup of mucus in lungs and pancreas? a. cystic fibrosis b. heart disease c. huntington's disease d. sickle cell anemia

Darwin’s hypothesis about how life changes over time is now called?