Current availability of carbon dioxide is limiting to C3 plants . This means that:
1. At low light intensity, C₃ plants respond to high CO₂ concentrations
2. Growing plants like tomatoes in carbon dioxide-rich environment is unlikely to increase yield
3. They show saturation in the rates of photosynthesis at carbon dioxide concentration higher than the current level
4. They have better water use efficiency and thus, adapted to warm tropical climates

Consider the two statements:

I. A poison that inhibits an enzyme of the Calvin cycle will also inhibit light reactions.

II. The light reactions require ADP and NADP+ which would not be produced in sufficient quantities if the Calvin cycle stopped.

1. Both I and II are correct and II explains I

2. Both I and II are correct but II does not explain I

3. I is correct but II is incorrect

4. Both I and II are incorrect

You add a water-soluble inhibitor of photosynthesis to the roots of a plant. The plant is actively transpiring. You are surprised that photosynthesis is not reduced. This is most likely due to:

1. Xylem vessels being dead at maturity

2. Inability of roots to take up water-soluble chemical

3. Endodermis

4. Transport of the inhibitor by phloem

Immediately after light becomes unavailable, the biosynthetic phase of photosynthesis continues for some time and then stops. If then, light is made available, the synthesis starts again. A logical conclusion of these observations will include:
I. Biosynthetic phase does not directly depend on the presence of light.
II. Biosynthetic phase depends on the products of light reactions.
III. Biosynthesis phase occurs only in the dark or in the absence of light.

Though chlorophyll a is the major pigment responsible for trapping light, other thylakoid pigments called accessory pigments are also involved. The accessory pigments:
I. Include xanthophylls and carotenoids but not chlorophyll b
II. Absorb light and transfer electrons to chlorophyll a
III. Enable a wider range of wavelength of incoming light to be reflected by green leaves
IV. Make Chlorophyll a more prone to photo-oxidation
The incorrect statements include:

In a photosystem:

Consider the given two statements:

Identify the incorrect match:

Consider the following two statements:
I. Plants with C₃ pathway have a single type of photosynthetic cell: the mesophyll cell.
II. Their bundle sheath cells do not contain chloroplasts.
1. Both I and II are correct
2. Only I is correct
3. Only II is correct
4. Both I and II are incorrect