Explore topic-wise MCQs in Biology.

This section includes 14 Mcqs, each offering curated multiple-choice questions to sharpen your Biology knowledge and support exam preparation. Choose a topic below to get started.

1.

Which of these is not an effect of water stress?

A. Closing of stomata
B. Increase in metabolism
C. Wilting of leaves
D. Reduction in surface area of leaves
Answer» C. Wilting of leaves
2.

Why do stomata close during water shortage?

A. To reduce CO<sub>2</sub> availability
B. To trap water
C. To increase metabolic activity
D. To increase the surface area of leaves
Answer» B. To trap water
3.

Which of these plants have the highest optimum temperature?

A. Tropical C<sub>3</sub>
B. Temperate C<sub>3</sub>
C. Tropical C<sub>4</sub>
D. Temperate C<sub>4</sub>
Answer» D. Temperate C<sub>4</sub>
4.

Which of these plants are grown in carbon dioxide enriched atmosphere?

A. Maize
B. Sugarcane
C. Tomato
D. Millets
Answer» D. Millets
5.

At what concentration do C4 plants show saturation?

A. 430 lL<sup>-1</sup>
B. 450 lL<sup>-1</sup>
C. 340 lL<sup>-1</sup>
D. 360 lL<sup>-1</sup>
Answer» E.
6.

Increase in CO2 concentration up to 0.5% causes an increase in photosynthesis. True or false?

A. True
B. False
Answer» C.
7.

What is the atmospheric concentration of carbon dioxide?

A. 0.3 0.4%
B. 3 4%
C. 0.03 0.04%
D. 0.003 0.004%
Answer» D. 0.003 0.004%
8.

What happens when the incident light on a plant is excessive?

A. RuBP undergoes oxidation
B. Vascular bundles lose functionality
C. Mesophyll cells are destroyed
D. Chlorophyll breaks down
Answer» E.
9.

At what percentage of sunlight does light saturation occur?

A. 30
B. 20
C. 10
D. 15
Answer» D. 15
10.

Which scientist gave the Law of Limiting Factors?

A. Hooke
B. Blackman
C. Fleming
D. Mendel
Answer» C. Fleming
11.

Which of these statements is false regarding the factors affecting photosynthesis?

A. The leaf orientation of a plant affects photosynthesis
B. Both internal and external factors affect photosynthesis
C. Photosynthetic rate is determined by a factor at sub-optimal level
D. Both CO<sub>2</sub> concentration in the environment and inside the plant affect photosynthesis
Answer» B. Both internal and external factors affect photosynthesis
12.

Which of these is not an external factor affecting photosynthesis?

A. Sunlight
B. Temperature
C. Leaf orientation
D. CO<sub>2</sub> concentration
Answer» D. CO<sub>2</sub> concentration
13.

What do the internal factors affecting photosynthesis dependent on?

A. External factors
B. Geographical area
C. Genetic predisposition
D. Species and sub-species
Answer» D. Species and sub-species
14.

Which of these is not an internal factor affecting photosynthesis?

A. Size
B. Age
C. Number
D. Water
Answer» E.