1. A mutation of a human gene blocks harmful viruses from infecting cells. How can the mutation be classified?

It is a beneficial mutation.

It is a neutral mutation.

It is a harmful mutation.

It is a deadly mutation.

It is a beneficial mutation.

Explanation: Mutations are permanent changes in the nucleotide sequence of a DNA. Mutations can beneficial, neutral and harmful or deleterious. When change in the nucleotide sequence of DNA a mutation enhances the effectiveness of a protein or improves the protein function, it is said to be beneficial. When a mutation causes the synthesis of a protein which have the same amino acid as the original protein and performs the same function as the original protein, it is said to be silent or neutral. When a mutation results in the synthesis of a protein with an altered amino acid sequence and a nonfunctional protein, it is said to be harmful.