A 25-year-old woman has a positive pregnancy

test based on the detection of the human chorionic gonadotrophin (hCG) hormone

in her urine. To be sure, she visits her gynaecologist the next day and asks

him to confirm the pregnancy with the help of blood tests, which are also based

on the determination of the value of this hormone in the blood. hCG is a

specific hormone that is present in the body only during pregnancy (except a

few specific pathological conditions). Choose correct statement about the

tissue that produces hCG during pregnancy?