Which definition is the best for “semipermeable membrane”? it is a barrier that prevents materials from moving from one side to the other. it is a barrier that allows materials to move freely from one side to the other. it is a barrier with tiny openings that let some, but not all, materials pass through. it is a barrier that materials move from one side to the other.

Option C, It is a barrier with tiny openings that let some, but not all, materials pass through

Explanation:

A semipermeable membrane is a biological membrane that allows some substances to pass through it. Such type of membranes are also referred as selectively permeable membrane as they do not allow all substances to pass through it non-distinctively.

For example the cell membrane , wall of arteries, wall of intestine etc.  are semipermeable membrane.

Hence, option C is correct.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.