Biology Trivia Questions and Answers

From the organs that keep you alive to the cells and chromosomes inside them, these biology trivia questions cover the living world from top to bottom. Each comes with a short explanation, making it a quick refresher for students and a solid round for any science quiz night.

8 questions · Every answer explained · Fact-checked October 2026

1. 1. Which organ pumps blood around the human body?

   • A. Lungs
   • B. Liver
   • C. Heart
   • D. Kidneys
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   C. Heart — The heart is a muscular pump that pushes blood through the arteries and veins of the circulatory system.

   Did you know? An adult heart beats roughly 100,000 times a day.

2. 2. Which gas do plants take in from the air to make their food?

   • A. Oxygen
   • B. Nitrogen
   • C. Carbon dioxide
   • D. Helium
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   C. Carbon dioxide — In photosynthesis, plants use sunlight to turn carbon dioxide and water into sugar, releasing oxygen.

   Did you know? Much of the oxygen we breathe comes from ocean algae, not land plants.

3. 3. How many legs does an insect have?

   • A. 4
   • B. 6
   • C. 8
   • D. 10
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   B. 6 — All adult insects have six legs, attached to the middle section of the body, the thorax.

   Did you know? Spiders have eight legs, which is why they aren't insects.

4. 4. Which part of the cell is often called its 'powerhouse'?

   • A. Nucleus
   • B. Ribosome
   • C. Mitochondrion
   • D. Golgi apparatus
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   C. Mitochondrion — Mitochondria produce most of a cell's ATP, the molecule cells use as an energy currency.

   Did you know? Mitochondria have their own DNA, which you inherit only from your mother.

5. 5. What is the largest organ of the human body?

   • A. Liver
   • B. Brain
   • C. Skin
   • D. Lungs
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   C. Skin — The skin covers the whole body and makes up roughly 15% of an adult's body weight.

   Did you know? You shed tens of thousands of dead skin cells every minute.

6. 6. How many chromosomes are in a typical human body cell?

   • A. 23
   • B. 44
   • C. 46
   • D. 48
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   C. 46 — Most human cells hold 46 chromosomes in 23 pairs — one set from each parent.

   Did you know? Chimpanzees, gorillas and orangutans each have 48.

7. 7. Which blood type is known as the universal red-cell donor?

   • A. AB positive
   • B. O negative
   • C. A negative
   • D. B positive
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   B. O negative — O negative red cells carry no A, B or RhD antigens, so almost anyone can receive them in an emergency.

   Did you know? AB positive is the opposite: the universal recipient for red cells.

8. 8. What type of cell division produces sperm and egg cells?

   • A. Mitosis
   • B. Meiosis
   • C. Binary fission
   • D. Budding
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   B. Meiosis — Meiosis halves the chromosome number, so each sperm or egg carries 23 chromosomes instead of 46.

   Did you know? Crossing over during meiosis shuffles genes, which is why siblings aren't identical.