Science MCQs

Practice multiple choice questions with instant feedback. Select an option to see if you're correct.

Total Questions
2100
Page 13 of 210
Question 121 Easy

Which gas is absorbed by plants during photosynthesis?

A
Oxygen
B
Carbon dioxide
C
Nitrogen
D
Hydrogen
Question 122 Medium

What happens to stomata in bright light?

A
Close
B
Open
C
Disappear
D
No change
Question 123 Medium

Which part of the leaf contains the most chloroplasts?

A
Upper epidermis
B
Lower epidermis
C
Palisade mesophyll
D
Spongy mesophyll
Question 124 Easy

What is the main function of the phloem?

A
Transport water
B
Transport food
C
Absorb sunlight
D
Store minerals
Question 125 Medium

Which factor does NOT affect the rate of photosynthesis?

A
Light intensity
B
Temperature
C
Wind speed
D
Carbon dioxide concentration
Question 126 Easy

What is the primary function of the respiratory system?

A
Pump blood
B
Exchange gases \(oxygen and carbon dioxide\)
C
Digest food
D
Filter toxins
Question 127 Medium

Which structure prevents food from entering the trachea?

A
Larynx
B
Epiglottis
C
Bronchus
D
Alveolus
Question 128 Easy

Where does gas exchange occur in the lungs?

A
Bronchi
B
Trachea
C
Alveoli
D
Diaphragm
Question 129 Medium

What happens to the diaphragm during inhalation?

A
It relaxes and moves up
B
It contracts and flattens
C
It remains unchanged
D
It expands sideways
Question 130 Easy

Which of the following is a product of aerobic respiration?

A
Lactic acid
B
Ethanol
C
Carbon dioxide and water
D
Nitrogen
Showing 121-130 of 2100 questions

Quick Stats

Total Questions 10900
easy 5797
medium 2983
hard 2120

Practice Tips

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Did You Know?

Practice Makes Perfect

Regular practice with MCQs can improve your test-taking speed and accuracy by up to 40%.

Active Recall

MCQs engage active recall, which is 50% more effective for long-term memory than passive reading.