Concept:Fertilization results in the formation of a single cell called a zygote.Explanation:A fertilized egg is produced when a sperm cell fuses with an ovum during fertilization.The cell formed by this fusion is known as a zygote.The zygote later undergoes cell division to become an embryo, then a foetus.The placenta is an organ that supports the growing foetus, not the fertilized egg itself.The ovum is the female gamete before fertilization.Answer:B. zygote.