Biology MCQs

Question #2041

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The plant tissue responsible for growth in length is:

A. Apical meristem

B. Sclerenchyma

C. Lateral meristem

D. Cambium

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Correct Answer: Option A

Explanation:
Apical meristems at root and shoot tips undergo cell division, causing primary growth (increase in length). Lateral meristems increase girth.

This question belongs to: Science Biology

Question #2042

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The blood group known as the universal donor is:

A. A positive

B. B negative

C. O negative

D. AB positive

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Correct Answer: Option C

Explanation:
O negative blood lacks A, B, and Rh antigens, so it can be transfused to any recipient without causing agglutination, making it the universal donor.

This question belongs to: Science Biology

Question #2043

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The normal human body temperature is about:

A. 39°C

B. 35°C

C. 37°C

D. 40°C

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Correct Answer: Option C

Explanation:
The average normal oral temperature is around 37°C (98.6°F). It is maintained by the hypothalamus through thermoregulation.

This question belongs to: Science Biology

Question #2044

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Which of the following is a water-borne disease?

A. Rabies

B. Cholera

C. Malaria

D. Tuberculosis

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Correct Answer: Option B

Explanation:
Cholera, caused by Vibrio cholerae, is transmitted through contaminated water and food. Malaria is vector-borne, TB airborne, rabies through animal bite.

This question belongs to: Science Biology

Question #2045

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The largest bone in the human body is:

A. Radius

B. Humerus

C. Tibia

D. Femur

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Correct Answer: Option D

Explanation:
The femur (thigh bone) is the longest, strongest, and heaviest bone, supporting body weight during standing and walking.

This question belongs to: Science Biology

Question #2046

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The smallest bone in the human body is the:

A. Malleus

B. Incus

C. Cochlea

D. Stapes

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Correct Answer: Option D

Explanation:
The stapes (stirrup) in the middle ear is the smallest bone, measuring about 3 mm. It transmits sound vibrations to the inner ear.

This question belongs to: Science Biology

Question #2047

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Which part of the eye is responsible for color vision?

A. Rods

B. Cones

C. Cornea

D. Pupil

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Correct Answer: Option B

Explanation:
Cone cells in the retina detect color (photopic vision). Rods are for dim light (scotopic) vision. The fovea has high cone density.

This question belongs to: Science Biology

Question #2048

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The enzyme that breaks down starch into sugar in the mouth is:

A. Trypsin

B. Lipase

C. Amylase

D. Pepsin

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Correct Answer: Option C

Explanation:
Salivary amylase (ptyalin) initiates starch digestion in the mouth, hydrolyzing starch to maltose. Pepsin digests proteins, lipase fats.

This question belongs to: Science Biology

Question #2049

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The deficiency of vitamin D in children causes:

A. Scurvy

B. Rickets

C. Beriberi

D. Pellagra

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Correct Answer: Option B

Explanation:
Rickets is characterized by weak, deformed bones due to impaired calcium deposition from lack of vitamin D. In adults, it's osteomalacia.

This question belongs to: Science Biology

Question #2050

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The polysaccharide stored in human liver and muscles is:

A. Cellulose

B. Glycogen

C. Starch

D. Chitin

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Correct Answer: Option B

Explanation:
Glycogen is the storage polysaccharide in animals, highly branched, stored in liver and muscles. Starch is plant storage, cellulose plant structural.

This question belongs to: Science Biology

Question #2051

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The protein responsible for muscle contraction are:

A. Collagen and elastin

B. Hemoglobin and insulin

C. Keratin and melanin

D. Actin and myosin

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Correct Answer: Option D

Explanation:
Actin (thin) and myosin (thick) filaments slide past each other during contraction, powered by ATP. Collagen is structural, hemoglobin transports oxygen.

This question belongs to: Science Biology

Question #2052

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The process by which plants lose water in the form of liquid droplets is:

A. Guttation

B. Translocation

C. Evaporation

D. Transpiration

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Correct Answer: Option A

Explanation:
Guttation is the exudation of water droplets from hydathodes, driven by root pressure under high humidity and low transpiration conditions.

This question belongs to: Science Biology

Question #2053

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The symbiotic nitrogen-fixing cyanobacterium in Azolla is:

A. Oscillatoria

B. Nostoc

C. Spirulina

D. Anabaena azollae

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Correct Answer: Option D

Explanation:
Anabaena azollae lives in cavities of the water fern Azolla and fixes atmospheric nitrogen. It is used as a biofertilizer in rice paddies.

This question belongs to: Science Biology

Question #2054

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The study of fungi is known as:

A. Pteridology

B. Phycology

C. Mycology

D. Bryology

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Correct Answer: Option C

Explanation:
Mycology deals with fungi, including yeasts, molds, and mushrooms. Phycology is study of algae, bryology mosses, pteridology ferns.

This question belongs to: Science Biology

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