Answer:
The correct answer is option D. The allele causes a certain type of protein to form
Explanation:
An allele does not form a type of gene but it is a variant or form of a gene itself that consists sequence of codes for a gene. Gene has two types of variants known as alleles in humans thus, humans called diploid organisms. Each gene has a certain number of an allele that leads to the specific type of protein by the process of gene expression.
Thus, the correct answer is - option D.
