A mutation is a change in the DNA of an organism. The change may or may not result a change to the physical characteristics (or phenotype) of the organism. Mutations that occur in a gamete (sperm or eggs) can be passed to the next generation, whereas mutations that occur in body (or 'somatic') cells may be harmless or may result in a disease such as cancer. Mutations can result in DNA being copied incorrectly. Mutagens can also cause mutations.

A point mutation is a change in one base in the genetic code. The change of one base to a different base (often caused by the DNA being copied incorrectly)-this is called a substitution mutation.

Match List – I with List – II.

Choose the correct answer from the options given below:

A-III, B-IV, C-I, D-II

The correct answer is Option (4) →A-III, B-IV, C-I, D-II

A. UV-Rays — III. Physical Mutagen
(UV rays are a type of physical mutagen that can cause mutations by damaging DNA, such as creating thymine dimers.)

B. Transposons — IV. Biological Mutagen
(Transposons, or "jumping genes," are biological agents that can move within the genome and cause mutations.)

C. Ethylene oxide — I. Chemical Mutagen
(Ethylene oxide is a chemical mutagen that can alter DNA by adding alkyl groups to nucleotides.)

D. Point mutation — II. Sickle cell anaemia
Mutation also arise due to change in a single base pair of DNA. This is known as point mutation. A classical example of such a mutation is sickle cell anemia