Biology
0Loading crowd target
0Loading crowd target
8correct to beat the crowd
186 free Biology trivia questions with answers — science & nature quiz, new questions added Oct 2026.
50 free biology trivia questions with answers. From the tiniest cells to the largest ecosystems, biology is the science of life. Test your knowledge of DNA, evolution, the human body, and the incredible diversity of living things.
30 of 186 questions with answers and explanations. Play the quiz
Q 01Which structure do prokaryotic cells such as bacteria lack?
Nucleus
The nucleus is what bacteria lack: their DNA sits loose in a region called the nucleoid, so the cell can start building a protein from a gene while that gene is still being copied.
Q 02Which pair of sex chromosomes do human males typically carry?
XY
XY is the male pair in humans, but birds do it the other way round: there it is the females that carry the mismatched pair, called ZW, while males have two matching Z chromosomes.
Q 03Which carnivorous plant catches insects between hinged leaves that snap shut?
Venus flytrap
The Venus flytrap closes only when its trigger hairs are touched twice in quick succession, a safeguard that stops the plant wasting energy by snapping shut on nothing.
Q 04What is the largest organ in the human body?
Skin
Skin is the body's largest organ and its protective barrier, which is why severe burns are so dangerous: with that covering gone, fluid leaks out of the body and germs get in.
Q 05Which condition results from an extra chromosome 21?
Down syndrome
Down syndrome arises when a child inherits three copies of chromosome 21 instead of the usual two, giving 47 chromosomes where most people have 46; the chance rises with the mother's age.
Q 06Which flightless bird, found only on Mauritius, died out in the seventeenth century?
Dodo
The dodo, a flightless relative of the pigeons, was exterminated not just by hungry sailors but by the animals they introduced to Mauritius.
Q 07What type of cell division produces two identical daughter cells?
Mitosis
Mitosis shares a cell's already-copied chromosomes equally between two new cells, which is how you grow and heal; cancer begins when the controls on that division break down.
Q 08What gas do plants primarily absorb from the atmosphere during photosynthesis?
Carbon dioxide
Carbon dioxide supplies the carbon that plants build into sugar and wood, so most of a tree's bulk is made from air, not drawn up from the soil as people tend to assume.
Q 09Which blood cells are responsible for fighting infections?
White blood cells
White blood cells rush to an infection and many die fighting it: the pus in an infected cut is full of dead white blood cells.
Q 10Which animals are the only mammals capable of true flight?
Bats
Bats fly by flapping a thin membrane stretched between long finger bones, so each wing is in effect a hand; flying squirrels, colugos and sugar gliders can only glide.
Q 11What pigment gives plants their green color?
Chlorophyll
Chlorophyll is the pigment in chloroplasts that captures light energy for the plant; it absorbs red and blue light but reflects green, which is why leaves look green.
Q 12Which organs filter waste from the blood to produce urine?
Kidneys
Kidneys filter far more fluid than you ever pass: almost all the water they strain from the blood is taken straight back, leaving only a litre or two of urine a day.
Q 13What is the term for an organism that makes its own food rather than eating other organisms?
Autotroph
An autotroph makes its own food, and not always from sunlight: around deep-sea vents, bacteria build sugar using chemicals such as hydrogen sulfide and feed whole animal communities.
Q 21What is the function of ribosomes in a cell?
Protein synthesis
Protein synthesis is the ribosome's whole job, and bacterial ribosomes differ enough from ours that antibiotics such as tetracycline can jam theirs while leaving our own untouched.
Q 22Which type of blood vessel carries blood away from the heart?
Arteries
Arteries carry oxygenated blood away from the heart to the body's tissues, except the pulmonary arteries, which carry deoxygenated blood to the lungs.
Q 23What is the term for the variety of life in a particular habitat or ecosystem?
Biodiversity
Biodiversity began as shorthand for 'biological diversity', coined in the mid-1980s for a Washington forum on the subject; the biologist Edward Wilson put the new word on the cover of the proceedings and it stuck.
Q 14Which structure do plant cells have that animal cells lack?
Cell wall
The cell wall is a tough coat built around cellulose, the most abundant organic compound on Earth; cotton fibre is about 90 percent cellulose, so a T-shirt is mostly plant cell wall.
Q 15Which bird lays the largest eggs of any living species?
Ostrich
The ostrich lays eggs weighing well over a kilogram, the biggest of any living bird, yet measured against the size of the adult it is actually a small egg.
Q 16Which Galápagos birds, studied for their varied beak shapes, are named after Darwin?
Finches
Finches is the name that stuck, though Darwin did not see that the birds belonged together until ornithologist John Gould examined his specimens in London and declared them one closely related group.
Q 17What are the tiny pores in a leaf's surface that control gas exchange called?
Stomata
Stomata are each flanked by two guard cells that swell or shrink to open and close the pore; plants lose most of their water through them, which is why many desert plants open them only at night.
Q 18Which part of the brain controls balance and coordination?
Cerebellum
The cerebellum fine-tunes movement, so damage there leaves a person able to move but swaying, walking with a wide, unsteady gait and missing objects they reach for.
Q 19What is the term for animals that eat both plants and meat?
Omnivore
Omnivore diets work as insurance: because they can switch between plants and prey, animals such as bears and pigs cope better than specialists when one kind of food runs short.
Q 20What scientist is known as the father of genetics?
Gregor Mendel
Gregor Mendel worked out the rules of inheritance by crossing pea plants at his monastery, but did not live to see them matter: his work was rediscovered in 1900, sixteen years after he died.
Q 24Which organelle is responsible for packaging and shipping proteins in a cell?
Golgi apparatus
The Golgi apparatus, reported by Camillo Golgi in 1898, was doubted as a mere staining artefact until electron microscopes confirmed it was real in the 1950s.
Q 25What is the process by which a caterpillar transforms into a winged adult called?
Metamorphosis
Metamorphosis is drastic: inside the chrysalis a caterpillar releases enzymes that dissolve most of its body, and the adult is rebuilt from small clusters of cells that survive.
Q 26What type of symbiotic relationship benefits one organism while harming the other?
Parasitism
Parasitism differs from predation in that the victim usually lives: a tick or tapeworm feeds on its host over a long period, so most parasites weaken rather than kill.
Q 27Which vitamin is produced by the human body when exposed to sunlight?
Vitamin D
Vitamin D needs strong sunlight, so far from the equator the body makes little or none in winter, which is why health services in countries such as Britain advise a supplement in the darker months.
Q 28What is the term for an organism that breaks down dead organic matter?
Decomposer
Decomposers such as moulds and bacteria are nature's recyclers: by breaking down dead leaves and bodies they release the nutrients locked inside, which plants then take up to grow.
Q 29The human heart's four chambers are two atria and two what?
Ventricles
Ventricles do the pumping, and the left one has the thickest wall of all because it must drive blood around the entire body, while the right only has to send it next door to the lungs.
Q 30Which principle did botanist Schleiden and physiologist Schwann establish in the late 1830s?
Cell theory
Cell theory grew out of a dinner conversation: when Schleiden talked about the nuclei of plant cells, Schwann recalled seeing the same thing in animal tissue, and both men promptly confirmed the resemblance.