Assertion: Water transport across biological membranes is too specific and too rapid to be explained entirely by diffusion through the lipid layer.
Reason: Water molecules are so small that they move relatively freely across the lipid bilayer, even though the middle zone is hydrophobic.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion: Short distance lateral transport from root hair to vascular cylinder via symplast route requires repeated crossings of plasma membranes as the solutes exit one cell and enter the next.
Reason: The symplast pathway consists of cell walls and extracellular spaces.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Nutrients pass easily through the sieve tube members of Phloem.
Reason: Though alive, sieve tube members lack such organelles as the nucleus, ribosomes and a distinct vacuole.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: The cohesive force of water in tracheids and vessels is stronger than the pull of gravity.
Reason: The tensile strength of a column of water varies inversely with the diameter of the column.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Given equal cross sectional areas of xylem, a plant with larger-diameter vessels can move more water up its stems than a plant with narrower tracheids.
Reason: The volume of liquid moving in a column per second is inversely proportional to ${\mathrm{r}}^4$ where r is the radius of the column, at constant pressure.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

What do A, B, C and D represent in the following figure?
 

Potometer works on the principle of
1. Potential difference between the tip of the tube and that of the plant
2. Amount of water absorbed equals the amount transpired
3. Osmotic pressure
4. Root pressure

The translocation of organic solutes in sieve tube members is supported by
1. Root pressure and transpiration pull
2. P-proteins
3. Mass flow involving a carrier and ATP
4. Cytoplasmic streaming

Plasmodesmata are:
1. Connections between adjacent cells
2. Lignified cemented layers between cells
3. Locomotory structures
4. Membranes connecting the nucleus with plasmalemma

Water vapor comes out from the plant leaf through the stomatal opening. Through the same stomatal opening, carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of the following options
1. Both processes cannot happen simultaneously
2. Both processes can happen together because the diffusion coefficient of water and CO₂ is different
3. The above processes happen only during night time
4. One process occurs during day time and the other at night