Which of the following best describes what can be found in chorionic villi?
A - Fetal blood vessels
B - Fetal blood vessels and maternal blood
C - Trophoblasts
D - Maternal blood
E - Fetal blood vessels and trophoblasts
Answer: E - Fetal blood vessels and trophoblasts
The CHORIONIC VILLI are finger-like structures of the placenta composed of embryo-derived trophoblasts that become surrounded by maternal blood (intervillus space).