LIFE SCIENCE

Detailed explanation-1: -There are three types of DNA Mutations: base substitutions, deletions and insertions. Single base substitutions are called point mutations, recall the point mutation Glu—–> Val which causes sickle-cell disease. Point mutations are the most common type of mutation and there are two types.

Detailed explanation-2: -Mutations can result from errors in DNA replication during cell division, exposure to mutagens or a viral infection. Germline mutations (that occur in eggs and sperm) can be passed on to offspring, while somatic mutations (that occur in body cells) are not passed on.

Detailed explanation-3: -Answer and Explanation: The correct answer to this question is B. They always cause a change to an organism’s genotype. Regardless of the cause of the change, a DNA sequence is always altered when it mutates.