a lot of questions will ask to id the extraembryonic membrane based on a description, specifically, "which membrane serves in gas exchange"..
both the chorion and allantois exchange gas between the embryo, and sometimes then answer will be one or the other. is there one that is dominant in the gas exchange role? unless the question lists other functions of the membrane, not sure how i would be able to tell..
both the chorion and allantois exchange gas between the embryo, and sometimes then answer will be one or the other. is there one that is dominant in the gas exchange role? unless the question lists other functions of the membrane, not sure how i would be able to tell..