Answer:
The correct answer is genes.
Step-by-step explanation:
The genes are the fundamental units of inheritance. The genes are passed to the offspring from the parents and comprise the information required to specify traits. The genes are aligned one after another on the compositions known as chromosomes. A chromosome comprises a lengthened and single molecule of DNA, of which only a part equivalent to a single gene. In humans, there are about 20000 genes aligned on their chromosomes.