A zygote is a single-celled structure, whereas a foetus is a multicellular structure with identifiable body parts.
Explanation
Human reproduction involves the fusion of male and female gametes to form a diploid cell, which subsequently undergoes mitotic divisions and differentiation. The developmental timeline progresses from a single cell to a complex, multicellular organism.- A zygote is a single-celled structure, whereas a foetus is a multicellular structure with identifiable body parts. is Correct: A zygote is the immediate product of fertilization (fusion of sperm and ovum) and is a single-celled structure. Through repeated cell division and differentiation, it develops into an embryo. The stage where all major body parts and organs are formed and become identifiable is termed the foetus.
- A zygote is formed in the uterus, whereas a foetus develops in the fallopian tube. is Incorrect: Fertilization, leading to the formation of the zygote, typically occurs in the fallopian tube (specifically the ampullary region). The developing embryo then travels to the uterus, implants in the uterine wall, and develops into a foetus within the uterus.
- A zygote contains only maternal genetic material, whereas a foetus contains material from both parents. is Incorrect: A zygote is formed by the fusion of a haploid sperm (paternal) and a haploid ovum (maternal). Therefore, it contains genetic material from both parents.
- A zygote represents the final stage of development, whereas a foetus represents the initial stage. is Incorrect: The zygote represents the initial stage of development. The foetus represents a later stage (typically from the ninth week of gestation until birth), following the embryonic stage.
Key Takeaway: The zygote is the unicellular beginning of life formed by fertilization, whereas the foetus is a multicellular, advanced developmental stage with distinct anatomical features.