Edward Jenner is credited with developing the first vaccine against: MCQ with Answer and Explanation

Edward Jenner is credited with developing the first vaccine against:
A. Smallpox
B. Rabies
C. Tuberculosis
D. Polio
Answer: Option A
Solution (By JKExamLibrary)
Edward Jenner, an English physician, is known as the 'father of immunology'. In 1796, he developed the world's first successful vaccine against smallpox. He observed that milkmaids who had contracted cowpox (a mild disease) were immune to smallpox. He inoculated a boy with material from a cowpox blister, successfully conferring immunity to smallpox, thus pioneering the concept of vaccination.

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Practice More Biology Questions

Question #1
Which of the following is NOT a characteristic of prokaryotic cells?
A. Circular DNA
B. Presence of membrane-bound organelles
C. Presence of 70S ribosomes
D. Cell wall generally present

Correct Answer: Option B


Explanation:
Prokaryotes lack membrane-bound organelles like mitochondria, Golgi apparatus, and endoplasmic reticulum. They have 70S ribosomes, a single circular chromosome in a nucleoid, and typically a cell wall (except Mycoplasma). Eukaryotes possess membrane-bound organelles. This fundamental difference defines the two major cell types in the living world.

This question belongs to: Science Biology
Question #2
The process by which bacteria convert atmospheric nitrogen into ammonia is called:
A. Nitrification
B. Ammonification
C. Nitrogen fixation
D. Denitrification

Correct Answer: Option C


Explanation:
Nitrogen fixation is the conversion of inert atmospheric N₂ into ammonia (NH₃) by free-living (e.g., Azotobacter) or symbiotic (e.g., Rhizobium) bacteria, or by industrial processes. Nitrification is the oxidation of ammonia to nitrites then nitrates. Denitrification converts nitrates to N₂ gas. Ammonification is the release of ammonia from organic nitrogen by decomposers. Fixed nitrogen is essential for plant growth.

This question belongs to: Science Biology
Question #3
Assertion (A): The leaves of cacti are reduced to spines.
Reason (R): Spines reduce water loss by transpiration.
A. Both A and R are true, and R is the correct explanation.
B. A true, R false.
C. A false, R true.
D. Both A and R are true, but R is not the correct explanation.

Correct Answer: Option A


Explanation:
Cacti, xerophytes, have spiny leaves to minimize surface area and transpiration, conserving water. Thus, R correctly explains A.

This question belongs to: Science Biology