Science · Unit 18

Frontiers of Science

The interdisciplinary science shaping the future

The units in this track cover settled science. This one covers the parts still moving, where the textbooks are being rewritten and the honest answer is often that nobody knows yet.

It covers biotechnology, nanotechnology, artificial intelligence and data science, and renewable energy technology - fields that are interdisciplinary by nature and do not fit neatly in any single subject.

This unit breaks down into 22 short steps and 130 questions, starting at difficulty 4 and building to 5. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.

Steps: 22
Questions: 130
Difficulty: 4-5

What this unit covers

Biotechnology
AI and Data Science
Nanotechnology
Renewable Energy Technology
Emerging Science

Where this fits

The last unit in the Science track. It assumes a working grasp of the method units.

Where people slip

Frontier science is provisional by definition. Some of what is described here will turn out to be wrong, and that is the normal operation of the process rather than a failure of it.

How the unit is structured

Frontiers of Science runs as 22 short steps that unlock in order. 16 are practice rounds and 6 are challenge rounds that pull together everything before them. Questions start at difficulty 4 and climb to 5 as you progress.

Step 1 · easierStep 22 · 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 130 in the unit altogether.

AI and Data Science

Fact or fibLevel 4
1. An AI model cannot be biased as long as its code is written correctly.
Answer: False
Bias often comes from the training data, so even perfectly correct code can produce biased predictions.
Fill the blankLevel 4
2. An artificial neural network learns by adjusting the connection ____ between its nodes during training.
- weightscorrect
- colors
- names
- shapes
Training tunes numerical weights (and biases) so the network's outputs better match the desired results.
Match the pairsLevel 4
3. Match each machine learning task to what it does.
Answer: Classification = Assigns a category label; Regression = Predicts a continuous number; Clustering = Groups unlabeled data points; Reinforcement learning = Learns from rewards and penalties
These are core problem types in machine learning, each suited to different goals.
Multiple choiceLevel 4
4. What distinguishes supervised machine learning from unsupervised learning?
- It trains on labeled examples with known answerscorrect
- It never uses any data at all
- It only ever works on images
- It requires no computation to run
Supervised models learn a mapping from inputs to known output labels, while unsupervised models find structure in unlabeled data.
Choose all that applyLevel 5
5. Which steps can help reduce overfitting in a machine-learning model? Pick all that apply.
- Collecting more training datacorrect
- Adding regularizationcorrect
- Using a simpler modelcorrect
- Training longer on the same tiny dataset
More training data, regularization, and a simpler model all fight overfitting; drilling harder on one tiny dataset makes it worse.
Guess the numberLevel 5
6. GPT-3 was released with roughly how many billion parameters?
Answer: 175 billion
GPT-3 had about 175 billion parameters, a scale-up that showed surprising few-shot abilities.

Biotechnology

Choose all that applyLevel 4
7. Which are real applications of biotechnology? Pick all that apply.
- Producing human insulin in engineered bacteriacorrect
- Developing pest-resistant genetically modified cropscorrect
- Gene therapy to treat an inherited diseasecorrect
- Generating electricity by nuclear fission
Biotech engineers living systems for medicine and agriculture; nuclear fission is a physics-based energy technology.
Fact or fibLevel 4
8. mRNA vaccines deliver genetic instructions telling cells to make a viral protein, not a live virus.
Answer: True
mRNA vaccines carry messenger RNA for a single viral protein, so they cannot cause the infection.
Fill the blankLevel 4
9. CRISPR was adapted from a bacterial ____ system that defends cells against invading viruses.
- immunecorrect
- digestive
- nervous
- circulatory
Bacteria use CRISPR arrays as an adaptive immune memory to recognize and cut viral DNA.
Match the pairsLevel 4
10. Match each biotechnology tool to its main function.
Answer: CRISPR-Cas9 = Editing specific DNA sequences; PCR = Amplifying DNA copies; Restriction enzyme = Cutting DNA at recognition sites; Gel electrophoresis = Separating DNA fragments by size
Each tool does a distinct job in the molecular biology toolkit.
Multiple choiceLevel 4
11. What is the primary purpose of the polymerase chain reaction (PCR)?
- To make many copies of a specific DNA sequencecorrect
- To permanently delete a gene
- To translate RNA into protein
- To stain cells for microscopy
PCR amplifies a targeted DNA region into millions of copies for analysis or testing.
Put in orderLevel 4
12. Put the three repeating steps of one PCR thermal cycle in order.
Answer: Denaturation: heat separates the DNA strands -> Annealing: primers bind to the target sequences -> Extension: polymerase builds new complementary strands
Each PCR cycle denatures the DNA, anneals primers, then extends new strands, roughly doubling the DNA each round.

Emerging Science

Build the sentenceLevel 4
13. Build a sentence about quantum computing.
Answer: Quantum computers use qubits to process information
Quantum computers replace classical bits with qubits that exploit superposition and entanglement.
Fact or fibLevel 4
14. A large enough quantum computer could break some of today's public-key encryption faster than any classical computer.
Answer: True
Shor's algorithm on a powerful quantum computer could factor large numbers efficiently, threatening RSA-style encryption.
Fill the blankLevel 4
15. Nuclear ____ joins light atomic nuclei to release energy, and is the goal of reactors such as ITER and other tokamaks.
- fusioncorrect
- fission
- decay
- digestion
Fusion powers the Sun; on Earth, tokamaks confine hot plasma to try to fuse hydrogen isotopes for energy.
Multiple choiceLevel 4
16. What key property lets a quantum bit (qubit) differ from a classical bit?
- It can exist in a superposition of 0 and 1 at oncecorrect
- It can only ever hold the value 0
- It is always physically larger than a byte
- It runs without using any energy
Superposition lets a qubit represent a combination of 0 and 1, helping some quantum algorithms explore many states together.
Odd one outLevel 4
17. Which is NOT an emerging low-carbon or climate technology?
- Coal-fired steam enginecorrect
- Green hydrogen electrolysis
- Direct air capture of CO2
- Grid-scale battery storage
Green hydrogen, direct air capture, and grid batteries are modern climate technologies; the coal-fired steam engine is a legacy fossil-fuel technology.
Picture questionLevel 4
18. 🚀 Which frontier technology does this represent, credited with sharply cutting the cost of reaching orbit?
- Reusable launch rocketscorrect
- Carbon capture plants
- Quantum computers
- Gene therapy
Reusable rockets that land and fly again, like the SpaceX Falcon 9 first stage, have greatly reduced launch costs.

Nanotechnology

Choose all that applyLevel 4
19. Which properties become dominant as a material is reduced to the nanoscale? Pick all that apply.
- A high surface-area-to-volume ratiocorrect
- Quantum confinement effectscorrect
- A large fraction of atoms sitting on the surfacecorrect
- Complete loss of all chemical reactivity
At the nanoscale, huge surface-to-volume ratios and quantum effects dominate, often boosting reactivity rather than removing it.
Fact or fibLevel 4
20. Some sunscreens use zinc oxide nanoparticles that block UV rays while looking transparent on the skin.
Answer: True
At the nanoscale, zinc oxide still absorbs and scatters UV light but the particles are too small to appear white, so the sunscreen looks clear.
Fill the blankLevel 4
21. A quantum dot emits a specific color of light that depends mainly on its ____.
- sizecorrect
- mass
- charge
- age
Because of quantum confinement, smaller quantum dots emit bluer light and larger ones emit redder light.
Guess the numberLevel 4
22. About how many nanometers wide is a DNA double helix?
Answer: 2 nm
The DNA double helix is roughly 2 nanometers in diameter, placing it firmly in the nanoscale.
Match the pairsLevel 4
23. Match each carbon nanomaterial to its structure.
Answer: Fullerene (C60) = Hollow spherical cage of carbon; Carbon nanotube = Rolled-up cylinder of graphene; Graphene = Single flat sheet of carbon atoms; Nanodiamond = Nanoscale crystalline carbon grain
Carbon forms distinct nanostructures - cages, tubes, and sheets - each with unique properties.
Multiple choiceLevel 4
24. Nanotechnology works with structures in which size range?
- 1 to 100 nanometerscorrect
- 1 to 100 micrometers
- 1 to 100 millimeters
- 1 to 100 picometers
The nanoscale spans roughly 1 to 100 nanometers, where one nanometer is one billionth of a meter.

Renewable Energy Technology

Choose all that applyLevel 4
25. Which are used for grid-scale energy storage? Pick all that apply.
- Pumped-hydro storagecorrect
- Lithium-ion battery bankscorrect
- Flywheelscorrect
- Burning more coal
Pumped hydro, large batteries, and flywheels all store energy to release later; burning coal is generation, not storage.
Fact or fibLevel 4
26. A lithium-ion battery stores energy chemically and can be recharged many times.
Answer: True
Lithium ions shuttle between the electrodes during charge and discharge, making the battery rechargeable.
Fill the blankLevel 4
27. A wind turbine converts the ____ energy of moving air into electricity.
- kineticcorrect
- nuclear
- chemical
- sound
Wind's kinetic energy spins the blades and generator, producing electrical energy.
Guess the numberLevel 4
28. Roughly what percentage of sunlight do typical commercial silicon solar panels convert into electricity?
Answer: 20 %
Most commercial silicon panels reach about 18 to 22 percent efficiency today.
Match the pairsLevel 4
29. Match each renewable technology to the energy source it harnesses.
Answer: Solar photovoltaic panel = Sunlight; Wind turbine = Moving air; Hydroelectric dam = Flowing water; Geothermal plant = Heat from inside the Earth
Each renewable technology taps a naturally replenished energy flow.
Multiple choiceLevel 4
30. A photovoltaic solar cell converts sunlight directly into what?
- Electricitycorrect
- Heat only
- Chemical fuel
- Sound
The photovoltaic effect frees electrons in a semiconductor when light strikes it, producing an electric current.

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 14 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
Match the pairs
Multiple choice
Odd one out
Picture question
Put in order
Sort into groups
Spell it
True or false
Type the answer

Practise Frontiers of Science

130 questions across 22 steps. Start with step one and crawl at your own pace.

Play this unit

More units in Science

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