Question

A gene said to be dominant if:
A. It express its effect only in homozygous stage
B. it expressed only in heterozygous condition
C. It expressed both in homozygous and heterozygous condition
D. it never expressed in any condition

Answer 1

Gene is nothing but the sequence of nucleotides that are found in DNA or RNA and this gene encodes for the synthesis of particular things such as proteins, whereas in the process of gene expression the DNA is copied to RNA where this can be directly functional, and it can be helpful for protein synthesis.

Complete answer:
Generally, genes are transmitted from the organisms to the offspring and this process is called inheritance.
The genes that make up different DNA sequences are called genotypes, and their character based on the inheritance is called the phenotype.
Each gene generally specifies the particular character and this is called an allele, for example, genes responsible for eye color have different alleles, such as brown color, black color, etc.
These alleles of the genes may present again as either dominant or recessive.
So the genes are said to be dominant, they give rise to their corresponding phenotypes, where they paired up with any other gene of the same character.
But the recessive genes are the ones where they give phenotypic expression, only when they paired up with another copy of the same genes.
Based on the inheritance of allele from each parent, they are again of different types such as homozygous and heterozygous.
If the offspring receives the same type of gene from each parent, then it is said to be homozygous and it may be dominant or recessive.
If the offspring receive different types of genes from each parent, then it is said to be heterozygous, in heterozygous, only dominant express the phenotypic trait.

So the correct option is C.

Note: Genes are of two types, that are dominant and recessive, the dominant gene will express the phenotypic trait, and the recessive one not express the character, and each individual would obtain the genes from both of parents, where if both are dominant then they are homozygous dominant, if both are recessive called as homozygous recessive.