Which statement regarding genes and evolution is true?
A. If an organism has a mutation, it will be less "fit" (less able to reproduce) than other organisms.
B. Today's plethora of microorganisms is the result of an extremely brief period of genetic recombination events.
C. Mutations function to prevent the offspring of an organism from evolving.
D. Random, heritable genetic mutations are a source of genetic variation. This variation is necessary for natural selection to occur.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.

the titanic would be the correct answer