Genes which code for a pair of contrasting traits are

The correct answer is Option (4) → Alleles

Option (1) Dominant genes — Incorrect. A dominant gene is only one member of a pair.

Option (2) Recessive genes — Incorrect. A recessive gene is only one member of a pair.

Option (3) Determinants — Incorrect. Determinants (factors) was Mendel’s word for units of inheritance in general.

Option (4) Alleles — Correct. Alleles are slightly different forms of a gene coding for a pair of contrasting traits.

Note: A similar question was also asked in CUET (UG) 2026 on 14-05-2026 (Slot 1).

NCERT Extract:
Mendel’s Laws of Inheritance – “… Based on these observations, Mendel proposed that something was being stably passed down, unchanged, from parent to offspring through the gametes, over successive generations. He called these things as ‘factors’. Now we call them as genes. Genes, therefore, are the units of inheritance. They contain the information that is required to express a particular trait in an organism. Genes which code for a pair of contrasting traits are known as alleles, i.e., they are slightly different forms of the same gene.”