Answer: Implantation of embryo outside the uterus (usually in fallopian tube); life-threatening as tube can rupture.
- A A pregnancy that involves two separate fetuses developing simultaneously together in the uterus
- B Implantation of embryo outside the uterus (usually in fallopian tube); life-threatening as tube can rupture
- C An early miscarriage occurring within the first few weeks of gestation, before any implantation issue
- D A pregnancy that results mainly from in vitro fertilization treatment in some cases
Correct answer: B. Implantation of embryo outside the uterus (usually in fallopian tube); life-threatening as tube can rupture
Explanation: Ectopic pregnancy: implantation outside the uterus. Most common site: fallopian tube (tubal pregnancy, ~95%). Risk factors: previous pelvic inflammatory disease, STIs. Life-threatening because the tube ruptures as embryo grows, causing internal bleeding. Diagnosed by ultrasound and hCG levels.
The human male reproductive system: sperm formed in the testis mature in the epididymis and travel via the vas deferens, mixing with secretions of the seminal vesicle, prostate and bulbourethral glands. Image: Wumingbai, CC BY-SA 4.0, via Wikimedia Commons.
Concept context
Male and female reproductive systems, gametogenesis, fertilization, implantation, pregnancy, and reproductive health.