Biology · Unit 12

Reproduction and Development

How life makes more life

Reproduction is where genetics stops being abstract. Gametes carry half a genome each, fertilisation combines them, and the variation that evolution works on is generated in the process.

The unit covers human reproductive anatomy, the hormone cycles that regulate it, fertilisation and pregnancy, and plant reproduction alongside - worth doing together, because seeing the same problem solved twice makes the general principle visible.

This unit breaks down into 20 short steps and 120 questions, starting at difficulty 1 and building to 3. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.

Steps: 20
Questions: 120
Difficulty: 1-3

What this unit covers

Human Reproduction
Gametes and Fertilisation
Pregnancy and Birth
Hormones and Cycles
Plant Reproduction

Where this fits

Needs DNA and Genetics for the gamete content to land. Feeds into Evolution and Ecology.

Where people slip

Hormone cycles are feedback loops, not schedules. Learning the sequence of events is much less useful than learning which hormone triggers or suppresses which other one.

How the unit is structured

Reproduction and Development runs as 20 short steps that unlock in order. 15 are practice rounds and 5 are challenge rounds that pull together everything before them. Questions start at difficulty 1 and climb to 3 as you progress.

Step 1 · easierStep 20 · harder

Challenge rounds

Example questions

30 real questions from this unit, with the answer and the reason behind it, grouped by what they practise. There are 120 in the unit altogether.

Gametes and Fertilisation

Fill the blankLevel 1
1. When a sperm cell joins with an egg cell, they form a single new cell called a ____.
- zygotecorrect
- gamete
- clone
- muscle
Fertilisation joins the sperm and egg to form a zygote, the first cell of a new individual.
Multiple choiceLevel 1
2. What is the male sex cell (gamete) in humans called?
- Spermcorrect
- Egg
- Zygote
- Pollen
The male gamete is the sperm cell.
Choose all that applyLevel 2
3. Which of these are true about the sperm cell compared with the egg cell? (Choose all that apply.)
- It is smallercorrect
- It can swim using a tailcorrect
- It is larger than the egg
- It carries the main food store
The sperm cell is small and can swim with its tail, while the egg cell is larger and holds the food store.
Guess the numberLevel 2
4. How many chromosomes does a human sex cell (gamete) carry?
Answer: 23 chromosomes
A human gamete carries 23 chromosomes, half the 46 found in an ordinary body cell.
Spell itLevel 2
5. Spell the word for when a sperm cell and an egg cell join together.
Answer: fertilisation
Fertilisation is the joining of the male and female gametes.
Picture questionLevel 3
6. 🥚 This is a human egg cell. Which structure hardens straight after fertilisation to block extra sperm from entering?
- The zona pellucidacorrect
- The acrosome
- The corona radiata
- A polar body
The cortical reaction hardens the zona pellucida around the egg, forming a barrier that blocks extra sperm.

Hormones and Cycles

Guess the numberLevel 1
7. About how many days does a typical menstrual cycle last?
Answer: 28 days
A typical menstrual cycle lasts about 28 days, though it varies between people.
Multiple choiceLevel 1
8. Which hormone is the main male sex hormone?
- Testosteronecorrect
- Oestrogen
- Progesterone
- Insulin
Testosterone is the main male sex hormone, produced mainly in the testes.
Build the sentenceLevel 2
9. Build the sentence describing what oestrogen does in the follicular phase.
Answer: oestrogen thickens the uterus lining
In the follicular phase, oestrogen repairs and thickens the uterus lining ready for a possible embryo.
Fact or fibLevel 2
10. A surge of luteinising hormone (LH) is what triggers ovulation.
Answer: True
The mid-cycle LH surge causes the mature follicle to rupture and release its egg.
Fill the blankLevel 2
11. The release of an egg from the ovary each cycle is called ____.
- ovulationcorrect
- menstruation
- fertilisation
- digestion
Ovulation is the release of a mature egg from the ovary, usually around the middle of the cycle.
Match the pairsLevel 2
12. Match each hormone to its role in the menstrual cycle.
Answer: FSH = Makes an egg mature; LH = Triggers release of an egg; Oestrogen = Builds the uterus lining; Progesterone = Maintains the uterus lining
Four main hormones work together to control the menstrual cycle.

Human Reproduction

Fact or fibLevel 1
13. A human baby develops inside the uterus (womb).
Answer: True
After fertilisation, the baby grows and develops in the uterus until birth.
Fill the blankLevel 1
14. The female organ that produces egg cells is the ____.
- ovarycorrect
- testis
- uterus
- stomach
The ovaries are the female organs that make and store egg cells.
Multiple choiceLevel 1
15. Which organ produces sperm cells in males?
- Testescorrect
- Ovaries
- Kidneys
- Bladder
Sperm cells are made in the testes.
Odd one outLevel 1
16. Which of these is NOT a female reproductive organ?
- Testiscorrect
- Ovary
- Uterus
- Oviduct
The testis is a male organ; the ovary, uterus and oviduct are all female organs.
Build the sentenceLevel 2
17. Build the sentence explaining how identical twins form.
Answer: one fertilised egg that splits into two
Identical twins come from a single fertilised egg that divides into two separate embryos.
Match the pairsLevel 2
18. Match each reproductive organ to its job.
Answer: Testes = Make sperm; Ovaries = Make eggs; Uterus = Where a baby grows; Oviduct = Carries the egg
Each reproductive organ has a specific role in making or supporting new life.

Plant Reproduction

Build the sentenceLevel 1
19. Build a sentence describing what pollination does.
Answer: Pollination moves pollen between flowers
Pollination is the transfer of pollen between flowers so that fertilisation can happen.
Fill the blankLevel 1
20. The male part of a flower, which makes pollen, is the ____.
- stamencorrect
- carpel
- petal
- root
The stamen is the male part of a flower and produces pollen.
Multiple choiceLevel 1
21. Which part of a flower is the female reproductive part?
- Carpelcorrect
- Stamen
- Petal
- Sepal
The carpel is the female part of a flower, which receives pollen and contains the ovules.
Choose all that applyLevel 2
22. Which conditions are needed for most seeds to germinate? (Select all that apply.)
- Watercorrect
- Oxygencorrect
- A suitable warm temperaturecorrect
- Light
- Added nitrate fertiliser
Germination needs water, oxygen and a suitable temperature; light and added nutrients are generally not required to start it.
Fact or fibLevel 2
23. Plants grown by asexual propagation, such as from cuttings or runners, are genetic clones of the parent plant.
Answer: True
Asexual reproduction involves no gametes, so the offspring are genetically identical to the single parent.
Match the pairsLevel 2
24. Match each flower part to its job.
Answer: Anther = Makes pollen; Stigma = Receives pollen; Ovary = Contains the ovules; Petal = Attracts insects
Each part of a flower plays a role in reproduction.

Pregnancy and Birth

Fill the blankLevel 1
25. The ____ cord connects the developing baby to the placenta.
- umbilicalcorrect
- spinal
- vocal
- nerve
The umbilical cord carries blood between the baby and the placenta.
Guess the numberLevel 1
26. About how many months does a human pregnancy last?
Answer: 9 months
A human pregnancy, or gestation, lasts about 9 months.
Choose all that applyLevel 2
27. Which substances pass from the mother to the baby across the placenta? (Choose all that apply.)
- Oxygencorrect
- Glucose (food)correct
- Waste carbon dioxide from the baby
- Large bacteria
Oxygen and glucose pass from mother to baby, while waste such as carbon dioxide passes the other way.
Fact or fibLevel 2
28. The placenta carries waste such as carbon dioxide away from the baby's blood.
Answer: True
The placenta removes waste like carbon dioxide and urea from the baby's blood into the mother's blood.
Multiple choiceLevel 2
29. What is the main job of the placenta during pregnancy?
- To exchange substances between the mother and the developing babycorrect
- To make the baby's bones
- To produce the mother's blood
- To store the baby's food for after birth
The placenta exchanges substances such as oxygen, nutrients and waste between the mother and the baby.
Odd one outLevel 3
30. Three of these hormones are produced by the placenta during pregnancy. Which one is the odd one out?
- Human chorionic gonadotrophin (hCG)
- Progesterone
- Human placental lactogen (hPL)
- Prolactincorrect
The placenta makes hCG, progesterone and human placental lactogen, but prolactin is released by the mother's pituitary gland, not the placenta.

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.

How you practise

This unit mixes 17 different question formats, so you are recalling and applying rather than recognising the same layout every time.

Build the sentence
Choose all that apply
Fact or fib
Fill the blank
Guess the number
Listen and choose
Match the pairs
Multiple choice
Odd one out
Picture question
Put in order
Sequence recall
Sort into groups
Spell it
Tap the pairs
True or false
Type the answer

Practise Reproduction and Development

120 questions across 20 steps. Start with step one and crawl at your own pace.

Play this unit

Read about Reproduction and Development

Explainers from our blog on what this unit covers. Each one ends with real questions from the bank.

What Is the Endocrine System? A Simple Guide to HormonesLearn how glands and hormones coordinate growth, metabolism, stress, reproduction, and other body functions clearly.August 14, 2026 · 5 min read

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