IB DP Biology- D3.1 Reproduction- IB Style Questions For SL Paper 1A -FA 2025
▶️ Answer/Explanation
Label X points to the testis, which produces sperm. Label Y indicates the sperm duct (vas deferens), which transports sperm toward the urethra. Label Z corresponds to the seminal vesicle, a gland that contributes fluid to semen. ✅ Answer: (A)
▶️ Answer/Explanation
Answer: (D) Ovulation
Explanation:
Ovulation is the process in which a mature egg cell is released from an ovarian follicle. This occurs due to a sharp increase in luteinizing hormone (LH), which triggers the rupture of the follicle and allows the egg to exit the ovary and enter the fallopian tube. This typically happens around the midpoint of the menstrual cycle.
Answer Evaluation:
A. Incorrect — Conception is the fusion of sperm and egg, not the release of the egg.
B. Incorrect — Fertilization occurs only after the egg has been released (ovulation).
C. Incorrect — Menstruation is the shedding of the uterine lining, unrelated to egg release.
D. Correct — Ovulation is the LH-triggered release of the egg from the follicle.
✅ Answer: (D)
▶️ Answer/Explanation
Answer: (C) Embryos
Explanation:
In in vitro fertilization (IVF)</strong), the egg and sperm are combined in a laboratory dish, where fertilization occurs outside the body. After fertilization, the resulting embryos are allowed to grow for a few days. Once they reach an early developmental stage, one or more embryos are transferred into the uterus, where they may implant and continue development.
Answer Evaluation:
A. Incorrect — Eggs are collected from the ovary and fertilized in the lab; they are not placed into the uterus.
B. Incorrect — Sperm fertilizes the egg in the lab, not inside the uterus during IVF.
C. Correct — Embryos are transferred into the uterus after fertilization.
D. Incorrect — A fetus is a later stage of development; IVF transfers embryos, not fetuses.
✅ Answer: (C)