Question

in osmosis, how does the cell membrane function? *
a) allows water to move in and out freely
b) removes solutes while blocking water
c) blocks all water entry completely
d) allows solutes but not water to enter

which pigment is most important for photosynthesis? *
a) chlorophyll
b) carotene
c) hemoglobin
d) keratin

Explanation:

First Question (Osmosis and Cell Membrane Function)

In osmosis, the cell membrane is selectively permeable. It acts as a semi - permeable barrier that allows water molecules to pass through freely (via aquaporins or simple diffusion) while restricting the free movement of most solutes. Option B is wrong as it says the opposite of what happens (it doesn't remove solutes while blocking water). Option C is incorrect because the cell membrane does not block all water entry. Option D is also wrong since in osmosis, it is water (not solutes) that moves across the membrane down its concentration gradient.

Second Question (Pigment Important for Photosynthesis)

Photosynthesis is the process by which plants (and some other organisms) convert light energy into chemical energy. Chlorophyll is the primary pigment in chloroplasts that absorbs light energy (especially in the visible light spectrum, mainly red and blue wavelengths) which is used to drive the photosynthetic reactions. Carotene is an accessory pigment that helps in light absorption but is not the most important. Hemoglobin is a pigment in blood for oxygen transport, not related to photosynthesis. Keratin is a structural protein in hair, nails, etc., and has nothing to do with photosynthesis.

Answer:

A) Allows water to move in and out freely