Suppose you want to isolate E. coli mutants incapable of synthesizing the amino acid arginine. You grow mutagenized bacteria on a master plate of complete defined media and make a replica plate (by pressing a velvet block onto the master plate and then pressing it onto the replica plate—bacteria will be transferred) on media lacking arginine. Colonies that grew on the master plate but not the replica plate are arginine-synthesizing mutants. In this example, the replica plate

The replica plate contain selective media.

Explanation:

Selective media allows the growth of a certain type of organisms while inhibiting the growth of other organisms.In the above scenerio,the replica plate contain selective media,it selectively favored growth of bacteria which cannot synthesis arginine.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.