MC, AS, AO QUESTIONS AND EXPERT VERIFIED CORRECT
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SECTION 1: GENERAL SCIENCE (GS) – 25 QUESTIONS
1. Which organelle is responsible for digesting worn-out cell parts and foreign
invaders?
A) Ribosome
B) Lysosome
C) Nucleus
D) Golgi apparatus
Correct Answer: B
Rationale: Lysosomes are membrane-bound sacs filled with hydrolytic enzymes
that break down waste materials, cellular debris, and foreign substances like
bacteria. They are often called the "garbage disposal" or "suicide bags" of the cell.
Ribosomes (A) are the sites of protein synthesis, not digestion. The nucleus (C)
contains the cell's genetic material (DNA) and controls cell activities. The Golgi
apparatus (D) modifies, sorts, and packages proteins and lipids for secretion or
delivery to other organelles. Therefore, B is the only correct answer.
2. Which of the following is an example of a chemical change?
A) Ice melting
B) Sugar dissolving in water
C) Iron rusting
D) Crushing a can
Correct Answer: C
Rationale: A chemical change produces a new substance with different chemical
properties. When iron rusts, it reacts with oxygen and water to form iron oxide
(rust), a new compound. Ice melting (A) is a physical change from solid to liquid
water—no new substance forms. Sugar dissolving in water (B) is a physical
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,change; the sugar can be recovered by evaporation. Crushing a can (D) is a
physical change in shape only. Thus, C is the correct answer.
3. What is the primary function of the circulatory system?
A) Exchange gases
B) Transport nutrients and oxygen
C) Produce hormones
D) Filter waste from blood
Correct Answer: B
Rationale: The circulatory system consists of the heart, blood vessels, and blood.
Its main role is to transport oxygen, nutrients, hormones, and waste products
throughout the body. Gas exchange (A) occurs in the respiratory system (lungs
and alveoli). Hormone production (C) is primarily the function of the endocrine
glands. Filtering waste from blood (D) is done by the kidneys (urinary system).
Therefore, B is the primary function.
4. Which layer of Earth's atmosphere contains the ozone layer?
A) Troposphere
B) Stratosphere
C) Mesosphere
D) Thermosphere
Correct Answer: B
Rationale: The ozone layer is located in the stratosphere, roughly 15–35 km above
Earth's surface. It absorbs about 97–99% of the sun's harmful ultraviolet (UV)
radiation. The troposphere (A) is the lowest layer where weather occurs. The
mesosphere (C) is where most meteors burn up. The thermosphere (D) is the
outermost layer and contains the ionosphere. Thus, B is correct.
5. The basic structural and functional unit of all living organisms is the:
A) Nucleus
B) Organ
C) Cell
D) Tissue
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,Correct Answer: C
Rationale: The cell is the smallest unit of life that can carry out all life processes.
All living things are made of one or more cells. The nucleus (A) is an organelle
within eukaryotic cells. An organ (B) is a group of tissues that perform a specific
function. A tissue (D) is a group of similar cells. Therefore, the cell (C) is the
fundamental unit.
6. Which organelle is known as the "powerhouse of the cell" because it produces
energy (ATP)?
A) Ribosome
B) Mitochondrion
C) Nucleus
D) Golgi apparatus
Correct Answer: B
Rationale: Mitochondria are the site of cellular respiration, where glucose and
oxygen are converted into ATP (adenosine triphosphate), the cell's energy
currency. Ribosomes (A) assemble proteins. The nucleus (C) stores DNA and
directs cell activities. The Golgi apparatus (D) packages and modifies proteins.
Hence, B is correct.
7. The heart has how many chambers?
A) 2
B) 3
C) 4
D) 5
Correct Answer: C
Rationale: The human heart has four chambers: the right atrium, right ventricle,
left atrium, and left ventricle. The right side receives deoxygenated blood and
pumps it to the lungs; the left side receives oxygenated blood and pumps it to the
body. Options A, B, and D are incorrect because they do not match the anatomical
structure of the human heart.
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, 8. Which type of muscle is under voluntary control?
A) Cardiac muscle
B) Smooth muscle
C) Skeletal muscle
D) Visceral muscle
Correct Answer: C
Rationale: Skeletal muscles are attached to bones and are under conscious
(voluntary) control, allowing movement. Cardiac muscle (A) is found in the heart
and is involuntary. Smooth muscle (B) lines internal organs such as the stomach
and intestines and is involuntary. Visceral muscle (D) is another term for smooth
muscle. Therefore, C is the only voluntary muscle type.
9. The largest organ in the human body is the:
A) Heart
B) Liver
C) Skin
D) Lungs
Correct Answer: C
Rationale: The skin is the largest organ by both surface area and weight,
accounting for about 15–20% of total body weight. It acts as a protective barrier,
regulates temperature, and provides sensation. The liver (B) is the largest internal
organ, but not the largest overall. The heart (A) and lungs (D) are smaller. Thus, C
is correct.
10. Which blood cells are primarily responsible for fighting infection?
A) Red blood cells
B) Platelets
C) White blood cells (leukocytes)
D) Plasma
Correct Answer: C
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