When and where do chorionic villi appear in humans ? State their function.

Explanation

Chorionic villi are finger like projections that arise from the trophoblast layer that develops in the zygote after it has undergone implantation.
Function of Chorionic Villi
1. It interdigitates with projections from uterine tissue to form a structure called the placenta, which is the connecting link between the mother and the foetus.
2. It facilitates the supply of oxygen and nutrients to the embryo.