Two molecules that can cross a lipid bilayer without from membrane proteins are o2 and co2, what property allows this to occur

O2 and CO2 are both nonpolar molecules that can easily pass through the hydrophobic interior of a membrane! Hope it helps

both the molecules are too small and have no charge therefore they can move across a membrane via gradient pressure from higher concentration to lower via simple diffusion. they don't need any atp or energy.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.