What is a clade?

a. a group of organisms with a shared ancestor

b. a trait that an ancestor did not have

c. a group with no shared traits

d. a trait that was passed along

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

When proteins are being produced by a cell, scientist say that the genes are question 2 options: activated turned off replicated deactivated

The fluid mosaic model of the membrane proposed that membranes