COMPREHENSIVE SCIENCE PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES 2026
Q&A | INSTANT DOWNLOAD PDF
1. What is the basic unit of heredity?
Gene
Genes carry the instructions for traits and are passed from parents
to offspring.
2. What type of bond involves the sharing of electron pairs between
atoms?
Covalent bond
Covalent bonds share electrons to achieve stable electron
configurations.
3. Which organelle is known as the “powerhouse of the cell”?
Mitochondria
Mitochondria produce ATP through cellular respiration.
4. Which of the following elements is a halogen?
Chlorine
Halogens are group 17 elements, including fluorine, chlorine,
bromine, iodine, and astatine.
,5. Which process converts solar energy into chemical energy?
Photosynthesis
Photosynthesis converts light energy into glucose using
chlorophyll.
6. What is the pH of a neutral solution at 25°C?
7
A neutral solution has equal hydrogen and hydroxide ion
concentrations.
7. Which blood type is known as the universal donor?
O negative
O negative blood lacks A, B, and Rh antigens, making it compatible
with all types.
8. What type of tissue connects bones to muscles?
Tendon
Tendons attach muscle to bone, enabling movement.
9. Which part of the brain regulates balance and coordination?
Cerebellum
The cerebellum manages muscle coordination and equilibrium.
10. What is the main gas responsible for the greenhouse effect?
Carbon dioxide
CO₂ traps heat in the atmosphere, contributing to global warming.
11. Which of the following is an example of a renewable energy
source?
Solar energy
Solar energy can be replenished naturally and continuously.
, 12. What is the function of red blood cells?
Transport oxygen
Red blood cells carry oxygen via hemoglobin.
13. What is the chemical symbol for potassium?
K
Potassium’s symbol comes from the Latin word “kalium.”
14. Which organ is responsible for filtering blood in the human
body?
Kidney
The kidneys remove waste and regulate fluid balance.
15. The atomic number of an element represents the number of:
Protons
The atomic number equals the number of protons in an atom’s
nucleus.
16. What is the SI unit of force?
Newton
One newton equals the force needed to accelerate one kilogram by
one meter per second squared.
17. Which macromolecule stores genetic information?
Nucleic acids
DNA and RNA are nucleic acids that carry genetic code.
18. What type of reaction absorbs heat?
Endothermic
Endothermic reactions require energy input from the
surroundings.