Mendel gave the name “factors” to-

The correct answer is Option (3) → Genes

(1) Autosomes — Incorrect. Autosomes are the chromosomes other than the sex chromosomes. One autosome carries a very large number of genes, so it is not a single factor.

(2) Chromosomes — Incorrect. Chromosomes are the thread-like structures that carry genes. Mendel knew nothing about them. The link between his factors and chromosomes was made later, in the chromosomal theory of inheritance.

(3) Genes — Correct. Mendel saw that something is passed unchanged from parents to offspring through the gametes. He called these units factors. We now call them genes. A gene carries the information needed to show one trait.

(4) Alleles — Incorrect. Alleles are the slightly different forms of the same gene, such as the genes for tall and dwarf height.

NCERT Extract:
Inheritance of One Gene – …