Which of the following statements is true? 1 All mutations are harmful.
2 Mutations are the only way to add new genes to a gene pool.
3 In substitution, DNA base pairs are deleted or lost during replication.
4 A mutation in the liver cell of a cat will be inherited by the cat's offspring.

Mutations are the only way to add new genes to a gene pool.

Explanation:

for 8 am not sure maybe yes?

for 9 if it is asking if the male is more or less it would be less

hope i even just a little : )

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds