A column of water within xylem vessels of tall trees does not break under its weight

because of

1. dissolved sugars in water

2. tensile strength of water

3. lignification of xylem vessels

4. positive root pressure

Transpiration and root pressure cause water to rise in plants by

1. Pulling it upward

2. pulling and pushing it, respectively

3. pushing it upward

4. pushing and pulling it, respectively

Which one of the following elements in plants is not remobilised?

1. Calcium

2. Potassium

3. Sulphur

4. Phosphorus

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

Substances that enter the living cells by facilitated diffusion are:

1. generally polar in nature

2. transported in the direction of the concentration gradient 

3. transported with the help of carrier proteins 

4. all of the above

Transpiration is very important for plants because it helps in 

1. the absorption of water from soil

2. the cooling of leaves at high temperature

3. the movement of water and minerals absorbed by roots to various parts of the plant

4. all of the above

Wooden doors swell up and get stuck during the rainy season. This is due to the

phenomenon of

1. imbibition

2. endosmosis

3. capillarity

4. deplasmolysis.

Stomata opens:

(1) in day time - for gaseous exchange

(2) in day time - no gaseous exchange

(3) in night time only - for gaseous exchange

(4) in night time only - no gaseous exchange

Which of the following helps in ascent of sap?

(1) Root pressure

(2) Transpiration

(3) Capillarity

(4) All of these

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

(1) A : carrier protein, B : symport, C : uniport, D : antiport

(2) A : carrier protein, B : uniport, C : antiport, D : symport

(3) A : carrier protein, B : antiport, C : symport, D : uniport

(4) A : carrier protein, B : uniport, C : symport, D : antiport