The evolution of C4 photosynthetic system is probably one of the strategies for:

1.	maximizing the availability of oxygen in spite of continuing high amount of water loss
2.	maximizing availability of water in spite of continuing high amount of carbon dioxide loss
3.	reducing the amount of water loss but leads to decreased availability of carbon dioxide
4.	maximizing the availability of carbon dioxide while minimizing water loss

Unlike water, all minerals cannot be passively absorbed by the roots. This is due to:
I. Minerals are present in the soil as charged particles
II. Concentration of minerals in soil is generally less than the concentration of minerals in roots
The correct statements are:
1. Only I
2. Only II
3. Both 1 & II are incorrect
4. Both 1 & II are correct

The control points where a plant adjusts the quality and types of solutes that reach the xylem are:

Unloading of mineral ions occurs at the fine vein endings through:
1. diffusion and, are passively taken up by the sink cells
2. active transport and, are passively taken up by the sink cells
3. diffusion and, are actively taken up by the sink cells
4. active transport and, are actively taken up by the sink cells

An analysis of xylem exudates will show that most of the nitrogen is carried as:
1. Inorganic ions
2. Ammonia dissolved in water
3. Dinitrogen
4. Organic compounds such as amino acids

Phloem sap is mainly:
1. Glucose and Water
2. Hormones and Amino acids
3. Water and Sucrose
4. Amino acids and water

Unlike xylem, the movement of sap in phloem is:
1. essentially unidirectional
2. from a sink to a source
3. independent of movement of water
4. in any direction from source to a sink

During mass flow in phloem, active transport is required:
1. For uploading sap
2. For unloading sap
3. Both for uploading and unloading the sap
4. Active transport is not required

Refer section 11.3.1, NCERT where it is stated that most of the water flow in the roots occurs via the apoplast. Why is this so?
1. Endodermis has suberized casparian strips
2. Root cortex cell lack plasmodesmata
3. Cortical cells are loosely packed
4. Root cortex is poorly organized

In sec 11.4, NCERT, it is mentioned that transpiration is affected by the canopy structure. This means that transpirational loss is lower in shaded leaves compared to sun exposed leaves higher in canopy. What would not be a reason for this?
1. Lower stomatal conductance
2. Lower leaf temperature
3. Lower air humidity
4. Lower air turbulence