Can someone help me with this

The options B and F are common for all respiratory surfaces.

Explanation:

All respiratory surfaces are involved in some form of gas exchange.

So firstly, the respiratory surface needs to have a moist membrane to be able to get the gases to diffuse properly. Option B is correct.

The surface area must be large and the surface of the respiratory system must be thin so that the maximum amount of gas can be diffused for increased efficiency. Option F is correct.

I hope this answer helps.