Ascientist wants to determine the effect of a new type of gasoline. he fills e car with normal gasoline and another identical car with the new gasoline. which is the control group?

the sphincter muscles at the end of the digestive tract is the anus.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.

trachea, alveoli, lung capillaries, arteries