Natural selection?

Question

Can someone help me on this question please, i do not understand a word it is saying.

Mutations can be harmful,helpful, or neutral. Natural selection acts on these mutations and selects for or against the mutation. Thus, organisms with a mutation that is selected for will have their fitness increased, while organisms with mutations that are selected against will have their fitness decreased.
What is natural selection acting on to drive this process? The process acts on the ?

1. Phenotype, which is an expression of the genotype
2.Genotype directly, and therefore not the phenotype
3. Correct allele combinations so that the species may prosper into the future
4. Genotype and, by extension acts on the genotype
5. DNA directly

Answer 1

I think you want; it acts on the phenotype and by extension, the genotype. ( there are still organism/genotype disputes on the unit of selection )

Answer 2

The first paragraph says that:

1. Some mutations are good. Some mutations are bad. Some mutations don't make any difference one way or another.
2. Natural selection happens when some condition in the environment makes life difficult for some organisms. The organisms that happen to have a lucky difference might survive when the others do not.

So you have to ask yourself ... "Is the situation letting them live because they have a certain gene, or are they living because they have a certain trait/characteristic?" The answer must be, "The lucky ones have some lucky trait or characteristic that helps them survive."

The answer that fits this explanation is the first one. Natural selection acts on the phenotype. (Phenotype is the actual trait or characteristic that the organism has as a result of what its genes say.) You know that a tall plant could be TT or Tt. If "tall" is the lucky trait, then TT will be fine or Tt will be fine. So natural selection is not choosing the genes. It's choosing the trait that is caused by the genes.