Answer:
I think the passage is trying to tell the reader that they shouldn't lose faith in people/animals just because they are elderly/weak when they are loyal to you because it will hurt their self-esteem.
The first three are the same as those found in DNA, but in RNA thymine is replaced by uracil as the base complementary to adenine. This base is also a pyrimidine and is very similar to thymine. Uracil is energetically less expensive to produce than thymine, which may account for its use in RNA.
C.
It is d, becuase you divide 500 by 15, and that is the closest answer
