PAX SCIENCE NLN QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES
Q&A 2026 |INSTANT DOWNLOAD
1. Which organelle is responsible for producing energy (ATP)
in a cell?
A. Ribosome
B. Nucleus
C. Mitochondria
D. Golgi apparatus
Rationale:
Mitochondria perform cellular respiration and generate ATP,
the cell’s main energy currency.
2. What is the main function of red blood cells?
A. Produce antibodies
B. Transport oxygen
C. Destroy bacteria
D. Produce hormones
Rationale:
Red blood cells contain hemoglobin which binds oxygen and
carries it to tissues.
,3. Which element is most abundant in the human body by
mass?
A. Carbon
B. Hydrogen
C. Nitrogen
D. Oxygen
Rationale:
Oxygen makes up about 65% of body mass due to its presence
in water and organic molecules.
4. What type of bond involves the sharing of electrons
between atoms?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Metallic bond
Rationale:
In covalent bonds atoms share electron pairs, creating stable
molecules.
5. Which system regulates body functions using hormones?
A. Nervous system
B. Digestive system
C. Endocrine system
D. Respiratory system
,Rationale:
The endocrine system releases hormones from glands to
regulate growth, metabolism, and homeostasis.
6. Which part of the neuron receives incoming signals?
A. Axon
B. Dendrites
C. Synapse
D. Myelin sheath
Rationale:
Dendrites receive electrical impulses from other neurons and
transmit them toward the cell body.
7. What is the pH of a neutral solution at 25°C?
A. 0
B. 1
C. 14
D. 7
Rationale:
A pH of 7 indicates equal concentrations of hydrogen and
hydroxide ions.
8. Which blood type is considered the universal donor?
A. AB
, B. A
C. B
D. O negative
Rationale:
O-negative blood lacks A, B, and Rh antigens, making it
compatible with most recipients.
9. What process do plants use to convert sunlight into
chemical energy?
A. Respiration
B. Fermentation
C. Photosynthesis
D. Transpiration
Rationale:
Photosynthesis converts carbon dioxide and water into glucose
and oxygen using sunlight.
10. Which law states that matter cannot be created or
destroyed?
A. Law of inertia
B. Law of thermodynamics
C. Law of conservation of mass
D. Law of acceleration
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES
Q&A 2026 |INSTANT DOWNLOAD
1. Which organelle is responsible for producing energy (ATP)
in a cell?
A. Ribosome
B. Nucleus
C. Mitochondria
D. Golgi apparatus
Rationale:
Mitochondria perform cellular respiration and generate ATP,
the cell’s main energy currency.
2. What is the main function of red blood cells?
A. Produce antibodies
B. Transport oxygen
C. Destroy bacteria
D. Produce hormones
Rationale:
Red blood cells contain hemoglobin which binds oxygen and
carries it to tissues.
,3. Which element is most abundant in the human body by
mass?
A. Carbon
B. Hydrogen
C. Nitrogen
D. Oxygen
Rationale:
Oxygen makes up about 65% of body mass due to its presence
in water and organic molecules.
4. What type of bond involves the sharing of electrons
between atoms?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Metallic bond
Rationale:
In covalent bonds atoms share electron pairs, creating stable
molecules.
5. Which system regulates body functions using hormones?
A. Nervous system
B. Digestive system
C. Endocrine system
D. Respiratory system
,Rationale:
The endocrine system releases hormones from glands to
regulate growth, metabolism, and homeostasis.
6. Which part of the neuron receives incoming signals?
A. Axon
B. Dendrites
C. Synapse
D. Myelin sheath
Rationale:
Dendrites receive electrical impulses from other neurons and
transmit them toward the cell body.
7. What is the pH of a neutral solution at 25°C?
A. 0
B. 1
C. 14
D. 7
Rationale:
A pH of 7 indicates equal concentrations of hydrogen and
hydroxide ions.
8. Which blood type is considered the universal donor?
A. AB
, B. A
C. B
D. O negative
Rationale:
O-negative blood lacks A, B, and Rh antigens, making it
compatible with most recipients.
9. What process do plants use to convert sunlight into
chemical energy?
A. Respiration
B. Fermentation
C. Photosynthesis
D. Transpiration
Rationale:
Photosynthesis converts carbon dioxide and water into glucose
and oxygen using sunlight.
10. Which law states that matter cannot be created or
destroyed?
A. Law of inertia
B. Law of thermodynamics
C. Law of conservation of mass
D. Law of acceleration
