The correct option is (a).
Explanation
In sexual reproduction, the formation of a new organism begins with the process of fertilization (syngamy), where a male gamete fuses with a female gamete to form a single diploid cell known as the zygote.
Statement-wise Analysis:
- Statement 1 is Correct: The zygote is the vital link that ensures the continuity of species between organisms of one generation and the next. It represents the first cell of a new individual, marking the beginning of the life cycle for sexually reproducing organisms.
- Statement 2 is Incorrect: A zygote is formed by the fusion of a haploid male gamete (sperm) and a haploid female gamete (ovum). Consequently, it contains genetic material (chromosomes) from both parents-half from the mother and half from the father-resulting in a diploid state.
- Statement 3 is Incorrect: The developmental sequence proceeds from the zygote to the embryo. The zygote is formed by fertilization, not by the division of the embryo. After formation, the single-celled zygote undergoes repeated mitotic divisions (cleavage) to eventually develop into a multicellular embryo.
Key Takeaway:
The zygote is the unicellular, diploid product of fertilization containing genetic material from both parents, and it undergoes cell division to form the embryo.