Alleles are:

Alleles are:
  1. Different phenotype
  2. True breeding homozygotes
  3. Different molecular forms of a gene
  4. Heterozygotes

Solution

Allele: Genes which code for a pair of contrasting traits are known as alleles i.e., they are slightly different forms of the same gene.

Heterozygous: An individual having two different alleles(Tt).

Phenotype: It is an observable morphological appearance of an organism.

Homozygous: Two alleles of  a gene are identical (TT or tt).

Asked in: NEET 2015 (Phase 1)

Practice more Principles of Inheritance and Variation questions on Aicharya