Which type of mutation affects the largest number of genes

Chromosomal mutation

Explanation:

Any modification that interferes with the number or structure of chromosomes in a cell is called a chromosomal mutation. Chromosomal mutations can be classified into numerical mutations, where there is change in the number of cell chromosomes, and structural mutations, where there is change in the shape or size of one or more cell chromosomes.

Numerical mutations are further subdivided into aneuploidies and euploidies. In aneuploidies, there is an increase or loss of one or more chromosomes; In euploidies, the increase or loss will be in complete chromosomal batches, also known as genomes.