NEET BIOLOGY

Detailed explanation-1: -The majority of mutations have neither negative nor positive effects on the organism in which they occur. These mutations are called neutral mutations. Harmful mutations may cause genetic disorders or cancer. Beneficial mutations are essential for evolution to occur.

Detailed explanation-2: -The majority of mutations are neutral in their effects on the organisms in which they occur. Beneficial mutations may become more common through natural selection. Harmful mutations may cause genetic disorders or cancer.

Detailed explanation-3: -Mutations result either from errors in DNA replication or from the damaging effects of mutagens, such as chemicals and radiation, which react with DNA and change the structures of individual nucleotides. All cells possess DNA-repair enzymes that attempt to minimize the number of mutations that occur (Section 14.2).

Detailed explanation-4: -B. Silent mutations are a result of the redundancy (degeneracy) of the genetic code: This is false, as silent mutations are the result of a base substitution that has no discernible effect on the amino acid sequence of a protein.