Subject

Biology

Life science, from the first cells to the molecular machinery of life - one tiny step at a time.

Biology on BrainSnail runs from the basic question of what makes something alive all the way to molecular genetics and biotechnology. The early units stay concrete: cells, the human body, plants and animals you can picture. Later units move into DNA replication, immunology, evolution and the machinery inside a cell.

The order matters here more than in most subjects, because biology builds. Cells explain tissues, tissues explain organs, and genetics explains inheritance and evolution. Working through the units in sequence means each new idea lands on something you already have.

Biology is the subject that turns your own body from a mystery into a mechanism. It is also the one that shows up most often in decisions you will actually make - about food, medicine, vaccination, and what to believe when someone tells you a study proved something.

Units: 18
Steps: 338
Questions: 2,067

Who this track is for

Starts at primary school level and reaches introductory university material in the genetics, molecular and immunology units.

How to approach it

Do the cell units before genetics - almost everything later refers back to them
Diagrams help enormously in biology, so sketch what you read about
Terminology is most of the difficulty, so treat vocabulary as its own task

Study guide · 9 min readHow to Learn BiologyBiology looks like the memorisation subject and mostly is not. A guide to the four ideas the whole subject reduces to, why the vocabulary is the real difficulty, and the order that stops each topic arriving as unrelated news.

What you will be able to do

Explain what happens to a meal between the plate and a cell
Read a Punnett square and say what it does and does not predict
Say why antibiotics do nothing against a cold
Follow a news story about gene editing without taking its framing on trust

The thing people get wrong

That biology is memorisation. The vocabulary is heavy, but almost every fact in the subject follows from a small number of ideas - cells, energy, inheritance and selection - and learning the ideas first makes the vocabulary stick instead of the other way round.

If you only do 3 units

Cells explain almost everything else in the subject, genetics is where a handful of rules produce enormous consequence, and the body systems unit is the one you will use.

What the questions look like

8 real questions from across the Biology track, easiest first, each with the answer and the reason behind it. Every unit page below has thirty more.

Build the sentenceLevel 1
1. Put the words in order to make a true sentence about what a rabbit eats.
Answer: A rabbit eats grass
A rabbit is a plant-eater, so a rabbit eats grass.
True or falseLevel 1
2. All living things are made of one or more cells.
Answer: True
One of the main ideas of cell theory is that every living thing is built from at least one cell.
Fact or fibLevel 1
3. The bladder stores urine until it is ready to leave the body.
Answer: True
The bladder is a stretchy sac that holds urine until you are ready to release it.
Multiple choiceLevel 1
4. Which nutrient, found in milk and cheese, helps build strong bones?
- Calciumcorrect
- Sugar
- Salt
- Fat
Calcium is a mineral in dairy foods that helps keep bones strong.
Multiple choiceLevel 1
5. What is a synapse?
- A tiny gap between two neuronscorrect
- The long fibre of a neuron
- A region of the brain
- A type of muscle
A synapse is the tiny gap or junction between two neurons where a signal is passed on.
Choose all that applyLevel 2
6. Which statements about ATP are correct? Select all that apply.
- ATP stores energy that cells can use quicklycorrect
- ATP is made when energy is released during respirationcorrect
- ATP provides the energy for active transportcorrect
- ATP is the gas that plants release in photosynthesis
ATP is made during respiration and stores energy that cells spend on jobs such as active transport; it is a molecule, not a gas.
Fill the blankLevel 2
7. Genes located close together on the same chromosome tend to be inherited together and are described as ____.
- linkedcorrect
- dominant
- recessive
- codominant
Linked genes lie on the same chromosome and do not assort independently, so they are usually passed on as a group unless separated by crossing over.
Fact or fibLevel 2
8. In aerobic respiration, oxygen serves as the final electron acceptor at the end of the electron transport chain, forming water.
Answer: True
Oxygen accepts electrons and protons at the end of the chain to form water, which lets the carriers keep passing electrons.

Units in Biology

Listed in the order they are meant to be worked through.

Practise Biology

2,067 questions, in tiny sessions you can finish in a few minutes.

Start playing

Where these questions come from. Each unit starts as a plan of the concepts it should cover and the difficulty it should span. Questions are written against that plan with AI assistance, then checked by a validator that rejects anything without a single defensible answer, an explanation, or plausible wrong options. How we write questions sets out the whole process, and corrections are fixed in the bank and reach the site and the app the same day.