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Biology Trivia Questions
Cells, organs, bones and how the human body actually works. 27 questions with answers, and a game you can play now.
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Biology questions are the ones people are most confident about and most often wrong. The body is familiar enough that everyone has a theory, which is why a round on it produces more argument than a round on physics.
The set below runs from counting bones and naming organs through to the mechanisms underneath: what blood carries, which system does what, and where the widely repeated claims about the human body came from and why they are not true.
All 27 biology trivia questions with answers
How many bones does an adult human skeleton normally have?
Answer: 206EasyBabies are born with about 270, which fuse over time.Why?
What gas do plants absorb from the air for photosynthesis?
Answer: Carbon dioxideEasyThey release oxygen as a by-product of the same reaction.Why?
Which organ in the human body produces insulin?
Answer: PancreasEasyClusters of cells called the islets of Langerhans do the work.Why?
How many chambers does the human heart have?
Answer: FourMediumTwo atria receive blood and two ventricles pump it out.Why?
What does DNA stand for?
Answer: Deoxyribonucleic acidMediumIts double-helix structure was described by Watson, Crick and Franklin's data.Why?
What blood type is known as the universal donor for red blood cells?
Answer: O negativeMediumIt carries neither A, B nor Rh D antigens for a recipient to react against.Why?
Which part of the brain controls balance and coordination?
Answer: CerebellumHardIt sits at the back of the skull, beneath the larger cerebrum.Why?
Which part of a plant normally takes up water from the soil?
Answer: The rootsEasyFine root hairs hugely increase the surface area available for absorption.Why?
Which organ pumps blood around the human body?
Answer: HeartEasyIt beats roughly a hundred thousand times in a day.Why?
Which of these animals is a mammal?
Answer: DolphinEasyDolphins breathe air, are warm-blooded and feed their young milk.
A caterpillar changes into a butterfly through which process?
Answer: MetamorphosisEasyInside the chrysalis most of the larval body is broken down and rebuilt.
Which blood cells carry oxygen around the body?
Answer: Red blood cellsMediumThey use haemoglobin, an iron-containing protein, to bind the oxygen.Why?
An animal that eats only plants is described as what?
Answer: HerbivoreMediumMany have specialised guts or extra stomachs to break down cellulose.
Which acid is found in the human stomach?
Answer: Hydrochloric acidHardA mucus lining stops the stomach from digesting itself.Why?
Which organelle is described as the powerhouse of the cell?
Answer: MitochondrionHardIt carries its own small loop of DNA, inherited from the mother.Why?
The bends, suffered by divers surfacing too fast, is caused by bubbles of which gas?
Answer: NitrogenHardDissolved nitrogen comes out of solution as the surrounding pressure drops.
Which blood vessel type has walls only one cell thick?
Answer: CapillariesHardThat thinness is what allows gases and nutrients to diffuse across.Why?
Which organ is protected by the skull?
Answer: BrainEasyThe adult skull is made of 22 bones that fuse together during childhood.
Which is the largest organ of the human body?
Answer: SkinEasyIn an adult it weighs around 4 kilograms and covers about 2 square metres.
Oranges and lemons are rich in which vitamin?
Answer: Vitamin CEasySailors once ate citrus to prevent scurvy, a disease caused by lacking it.
Including wisdom teeth, how many teeth does an adult human normally have?
Answer: 32EasyChildren have 20 milk teeth, which start falling out at around age six.
Which pigment gives plants their green colour?
Answer: ChlorophyllMediumIt absorbs red and blue light and reflects green, which is why leaves look that colour.
The spinal cord belongs to which body system?
Answer: Nervous systemMediumIt carries signals between brain and body and handles some reflexes without the brain at all.
Insulin regulates the level of what in the blood?
Answer: GlucoseMediumToo little insulin lets blood sugar climb, the hallmark of diabetes.
How many pairs of chromosomes does a typical human body cell contain?
Answer: 23 pairsHardThat makes 46 in total, half inherited from each parent.
Which part of the eye controls how much light enters it?
Answer: IrisHardIt widens the pupil in dim light and narrows it in bright light.
Hair and nails are made mainly of which protein?
Answer: KeratinHardThe same protein forms feathers, hooves and horns in other animals.
Answer key
- 206
- Carbon dioxide
- Pancreas
- Four
- Deoxyribonucleic acid
- O negative
- Cerebellum
- The roots
- Heart
- Dolphin
- Metamorphosis
- Red blood cells
- Herbivore
- Hydrochloric acid
- Mitochondrion
- Nitrogen
- Capillaries
- Brain
- Skin
- Vitamin C
- 32
- Chlorophyll
- Nervous system
- Glucose
- 23 pairs
- Iris
- Keratin
How to play
- Pick a mode: multiple choice, true or false, a 60-second sprint, or the daily quiz.
- Answer with a tap, or press 1 to 4 on a keyboard. The right answer appears straight away with a line explaining it.
- Finish the round to see your score, copy the result grid, and step up a difficulty.
- Hosting a night? The full biology trivia questions list and a separate answer key are printed below, and the print layout drops the game and keeps the paper.
The wider round
These come from the science set, which has 100 questions across 6 themes, plus tiebreakers and host notes. Science trivia