Question

Assertion
The zygote developed from sexual reproduction is diploid.
Reason
In sexual reproduction, haploid gametes fuse and form zygote.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
C. Assertion is correct, but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Sexual reproduction is the prevalent form of reproduction in Eukaryotes. In this process, two organisms are involved in opposite sexes. Both the individuals form and release gametes that fuse to give rise to a new cell. The chromosome number is maintained in the above process.

Complete answer:
Organisms have a fixed number of chromosomes. It varies from species to species. The chromosomes are present in pairs and the organism is known as a diploid organism.
During reproduction, the parents have to ensure that the number of chromosomes are the same in their offsprings to make them viable. This is easier in asexual mode of reproduction where parents clone themselves to produce daughter progenies. In sexual reproduction, however it is a bit complicated since the process involves fusion of gametes of either sex.
This can be achieved by the process of meiosis cell division during gamete formation. Meiosis or reduction division is the process in which cells divide twice to produce four daughter cells, each with half the number of chromosomes of the parent cell. The daughter cells are known as haploid cells. Therefore, we can say that the gametes are haploid in nature, that is they contain half the number of chromosomes present in the parents.
In sexual reproduction, the haploid gametes from the female and the male parent fuse by a process called fertilization. It results in the formation of a diploid cell called the zygote. Fertilization restores the normal chromosome count in the zygote.
For example, in humans, the diploid number of chromosomes is 46 or 23 pairs. The gametes, that is sperms and ovum are haploid, each containing 23 chromosomes. The fusion of the gametes results in the formation of a diploid zygote. The process maintains the chromosome number in the offspring.
Therefore, we can say that Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

Hence, the correct option is (A).

Note: Organisms are diploid in nature. However, the gametes of species that reproduce by sexual reproduction are haploid, that is they contain half the number of chromosomes as the organism. The haploid gametes fuse to form the zygote which is diploid. The zygote undergoes repeated cell division and development resulting in the formation of the young one.