Addictive Substances such as drugs and alcohol work by altering the levels of what in the brain?

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.

trachea, alveoli, lung capillaries, arteries

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.