Concept:Fertilisation creates a zygote, which becomes an embryo, implants in the uterus, and later becomes a foetus with recognisable body parts.
Explanation:The sperm and egg fuse to form a single-celled
zygote (W).
This zygote divides many times to become a ball of cells called an
embryo (X).
The embryo then implants into the soft wall of the
uterus (Y) for further growth.
When all major body parts are visible and developed, the stage is called a
foetus (Z).
Thus, the correct sequence is: zygote → embryo → uterus → foetus.
Answer:B. zygote, embryo, uterus, foetus