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.

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

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

Assertion: Pits connecting individual tracheids and vessels members to other tracheids or vessels is an adaptation against cavitation.
Reason: Air bubbles can easily pass through the pits clearing the tracheids and vessels of cavitation.

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: Turgor in guard cells results from the active uptake of ${\mathrm{K}}^{+}$
Reason: The energy required to move the ions across the guard cell membranes comes from ATP-driven ${\mathrm{H}}^{+}$ pump.

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: Increased turgor in guard cells opens stomata.
Reason: Rings of cellulose microfibrils prevent the width of the guard cells from swelling, and only allow the extra turgor pressure to elongate the guard cells.

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.

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R): 

In the light of the above statements choose the correct answer from the options given below: