Chorionic villi originate from

Chorionic villi originate from the trophoblast, specifically the syncytiotrophoblast layer.

After implantation, finger-like projections called chorionic villi develop on the trophoblast. The chorionic villi extend into the uterine tissue, and maternal blood surrounds them. As the chorionic villi and uterine tissue interdigitate, they collectively form the placenta, a crucial organ that facilitates the exchange of nutrients, gases, and waste products between the developing embryo (foetus) and the maternal body during pregnancy.