Final answer:
The amniotic and chorionic cavities are the obliterated cavities as the amniotic cavity enlarges. The pleural, pericardial, and peritoneal cavities are serous cavities that serve to reduce friction between organs and the body wall.
Step-by-step explanation:
As the amniotic cavity enlarges during embryonic development, the two cavities that obliterate are the chorionic and amniotic cavities. Option (d) Amniotic and Chorionic cavities is the correct choice. The amniotic cavity, formed around the inner cell mass and the trophoblast, is filled with amniotic fluid that protects the developing fetus. The chorion, along with the amnion, provides protection to the embryo.
The pleural cavity is a serous cavity that surrounds the lungs and is lined by the pleura, which consists of two layers - the visceral and parietal pleura. The pericardial cavity is another serous cavity that surrounds the heart and is enclosed by the pericardium. The peritoneal cavity is the third serous cavity surrounding several organs in the abdominopelvic region. These cavities reduce friction between organs and the body wall, providing protection to the enclosed viscera.