With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?
1. Increasing atmospheric ${\mathrm{CO}}_2$ concentration up to 0.05 % can enhance ${\mathrm{CO}}_2$ fixation rate
2. ${\mathrm{C}}_3$ plants respond to higher temperatures with enhanced photosynthesis while ${\mathrm{C}}_4$ plants have much lower temperature optimum
3. Tomato is a greenhouse crop which can be grown in ${\mathrm{CO}}_2$ – enriched atmosphere for higher yield
4. Light saturation for ${\mathrm{CO}}_2$ fixation occurs at 10% of full sunlight

Assertion: Not all organisms use carbon dioxide as a source of carbon atoms to carry out photosynthesis.
Reason: Photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon.

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 Calvin cycle in most plants occurs during daylight.
Reason: None of the steps of the Calvin cycle require light directly

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: Action spectrum of photosynthesis is much broader than the absorption spectrum of chlorophyll a.
Reason: Accessory pigments with different absorption spectra are also present in chloroplasts.

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: Photophosphorylation in chloroplasts and oxidative phosphorylation in mitochondria are different.
Reason: In chloroplasts the high energy electrons come from food while in mitochondria they come from water.

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:

Assertion: Transfer of electrons from the split water molecule to P${680}^{+}$ is easy.
Reason: P${680}^{+}$ is the strongest biological oxidizing agent known.

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 electrons of NADPH are more readily available for the reactions of Calvin cycle than those of water.
Reason: Two electrons are required for the reduction of NADP⁺ to NADPH.

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: Mutant plants that are not able to carry out cyclic electron flow do not grow well in intense light conditions.
Reason: Cyclic electron flow may be photoprotective.

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: Plastocyanin moves within the thylakoid membranes and plastoquinones move through the thylakoid lumen.
Reason: Plastocyanin is lipid soluble while plastoquinones are not.

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