Question

Diploid zygote is formed by the fusion of male and female gametes. This process

(A) Fertilization
(B) Budding
(C) Pollination
(D) Spore

Answer 1

Hint: The fusion of haploid gametes, egg, and sperm to form the diploid zygote is fertilization. Fertilization restores the chromosome number. The offspring are produced by the growth of the fusion product of gametes called a zygote.

Complete answer:
During fertilization, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane that block the entry of additional sperms. Thus, it ensures that only one sperm can fertilize an ovum. The secretions of the acrosome help the sperm enter into the cytoplasm of the ovum through the zona pellucida and the plasma membrane. This induces the completion of the meiotic division of the secondary oocyte. The second meiotic division is also unequal and results in the formation of a second polar body and a haploid ovum. The haploid nucleus of the sperms and that of the ovum fuse together to form a diploid zygote.
Budding is the mode of asexual reproduction in which new organisms develop as outgrowth or buds from a parent. (i) Exogenous/External budding, The bud develops externally on the parent. In the young condition, the two are internally connected to provide nourishment to the bud. Later on, the bud enlarges and becomes nutritionally independent. It then separates as a new individual, for example, yeast, hydra. (ii) Endogenous/ Internal budding, internal buds occur in sponges to help in dispersal as well as perennation.
Pollination is the transfer of pollen grains from anthers to the stigma. It is of two types: Self-pollination and cross-pollination.
Self-pollination is the transfer of pollen grains from anthers to the stigma of the same or genetically similar flower. It is possible only when anthers and stigma mature simultaneously. The phenomenon is called homogamy.
Cross-pollination is the transfer of pollen grains from the anthers of one flower to the stigma of a genetically dissimilar flower. Cross-pollination is also called xenogamy.
Spore formation is a method in Asexual reproduction. Many spores are stored in sacs called sporangia. Spores form part of the life cycles of many plants, algae, fungi, and protozoa.

So, the correct answer is option A i,e Fertilization.




Note: Asexual reproduction is the type of reproduction in which only one parent is involved. Formation of new young individuals from a specialized or unspecialized part of single-parent without the formation and fusion of gametes.