Which extraembryonic membrane carries on gas exchange?Multiple Choiceamnionchorionallantoisyolk sac

The extraembryonic membrane responsible for gas exchange is the allantois.

Explanation

1. Amnion: This membrane primarily serves to provide a protective cushioning around the embryo and maintains the amniotic fluid.
2. Chorion: While the chorion does play a role in forming the placenta and facilitates nutrient and gas exchange indirectly, it is the allantois that is primarily involved in gas exchange directly.
3. Allantois: This membrane develops into blood vessels that allow for the exchange of gases (oxygen and carbon dioxide) between the embryo's blood and the surrounding environment, making it crucial for respiratory functions in embryos of many species.
4. Yolk sac: This membrane mainly provides nutrients and is involved in early blood cell formation, but does not play a primary role in gas exchange.

Final Answer

Thus, the correct answer is allantois, as it specifically carries out the function of gas exchange among the extraembryonic membranes listed.