Selected MCQ

Current Question
Assertion: Vaccines help prevent some diseases. Reason: Vaccines weaken the body’s immune response.
  • A. Both are true and the reason correctly explains the assertion
  • B. Both are true but the reason does not explain the assertion
  • C. Assertion is true but reason is false
  • D. Assertion is false but reason is true
Correct Answer: C
Explanation:
Vaccines help prevent disease, but they strengthen immune defense rather than weaken it.
Related Question 1
Assertion: Birds have hollow bones. Reason: Hollow bones help reduce body weight for flight.
  • A. Both are true and the reason correctly explains the assertion
  • B. Both are true but the reason does not explain the assertion
  • C. Assertion is true but reason is false
  • D. Assertion is false but reason is true
Correct Answer: A
Explanation:
Hollow bones are a flight adaptation because they reduce body weight.
Related Question 2
Assertion: Iron objects rust faster in moist air. Reason: Moisture helps oxidation take place.
  • A. Both are true and the reason correctly explains the assertion
  • B. Both are true but the reason does not explain the assertion
  • C. Assertion is true but reason is false
  • D. Assertion is false but reason is true
Correct Answer: A
Explanation:
Moist air promotes oxidation, which causes rusting.
Related Question 3
Assertion: Plants need sunlight for photosynthesis. Reason: Photosynthesis helps plants prepare food.
  • A. Both are true and the reason correctly explains the assertion
  • B. Both are true but the reason does not explain the assertion
  • C. Assertion is true but reason is false
  • D. Assertion is false but reason is true
Correct Answer: B
Explanation:
Both statements are true, but the reason does not explain why sunlight is needed.
Related Question 4
Assertion: Glass windows crack when heated unevenly. Reason: Uneven heating causes unequal expansion in different parts of the glass.
  • A. Both are true and the reason correctly explains the assertion
  • B. Both are true but the reason does not explain the assertion
  • C. Assertion is true but reason is false
  • D. Assertion is false but reason is true
Correct Answer: A
Explanation:
Unequal expansion creates stress in the glass and causes cracking.
Related Question 5
Assertion: A compass needle points north-south. Reason: Earth acts like a giant magnet.
  • A. Both are true and the reason correctly explains the assertion
  • B. Both are true but the reason does not explain the assertion
  • C. Assertion is true but reason is false
  • D. Assertion is false but reason is true
Correct Answer: A
Explanation:
The compass aligns with Earth’s magnetic field.