Answer: The correct answer is option D.
Explanation:
In diploid organism, chromosomes are present in pair. One chromosome is inherited from mother and one from father. The chromosomes pair is termed as homologous chromosomes. They are similar in shape, size, number of genes present, sequence of the genes, position of centromere, et cetere.
Thus, option A is incorrect.
However, the genes may have different allele. For example chromosome 1 (maternal) contains one dominant allele, say T, while chromosome 1 (paternal) contains recessive allele at the same locus, say t,.
So, if an organism contains same alleles for the trait then, it is termed as homozygous for that trait. It can either be homozygous dominant (TT) or homozygous recessive (tt).
Thus, option B and C are incorrect.
However, of an organism contains two different alleles for the trait then it is termed as heterozygous for that trait (Tt). The phenotype is usually resulted from the expression of dominant allele.
Hence, option D is the correct answer.
