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GED Science Practice Questions with Answers

GED Science is a reasoning test wearing a science costume - most items hand you a passage, a diagram or a data table and ask what it means. These eight practice questions cover the content you still have to know cold, each worked out step by step.

The Science test gives you 90 minutes for roughly 34 to 40 items, weighted about 40% life science, 40% physical science and 20% Earth and space science. You get an on-screen TI-30XS calculator and a formula reference throughout. The good news: you are rarely asked to recall an obscure fact. You are asked to read carefully, apply a handful of core ideas, and pull conclusions out of data. Here are eight questions in the real test's style. Try each one before opening the solution.

Question 1 - Where a cell gets its energy

Which cell structure releases most of the usable energy a eukaryotic cell needs to function?
  • A. Ribosome
  • B. Mitochondrion
  • C. Golgi apparatus
  • D. Cell membrane
Show the solution

Cellular respiration takes the chemical energy stored in glucose and converts it into ATP, the molecule cells actually spend. That conversion happens inside the mitochondria, which is why cells with high energy demands - muscle cells, for instance - carry far more of them.

Ribosomes build proteins, the Golgi apparatus packages and ships them, and the cell membrane controls what enters and leaves. None of those produce ATP.

Answer: B. Mitochondrion

The GED often phrases this as a function question rather than a naming question. Learn what each organelle does, not just what it is called.

Question 2 - Photosynthesis and respiration

Photosynthesis and cellular respiration are often described as opposite processes. Which statement best explains why?
  • A. Both processes release oxygen as a waste product.
  • B. The products of one process are the reactants of the other.
  • C. Both processes occur only during daylight hours.
  • D. Both processes break glucose down into carbon dioxide.
Show the solution

Photosynthesis takes in carbon dioxide and water and uses light energy to build glucose, releasing oxygen. Cellular respiration takes in that glucose and oxygen and releases carbon dioxide and water, freeing energy as ATP.

Line the two up and the outputs of each are the inputs of the other. That cycle is what keeps carbon and oxygen moving through an ecosystem.

Answer: B. The products of one process are the reactants of the other.

C is a classic distractor - photosynthesis needs light, but respiration runs around the clock in plants and animals alike.

Question 3 - Reading a Punnett square

In a certain species, brown fur (B) is dominant over white fur (b). Two heterozygous brown-furred parents (Bb) produce offspring. What is the probability that an offspring will have white fur?
  • A. 0%
  • B. 25%
  • C. 50%
  • D. 75%
Show the solution

Cross Bb with Bb and the four equally likely combinations are BB, Bb, Bb and bb. White fur is recessive, so it only shows up when both alleles are lowercase.

Only one of the four outcomes is bb, so the probability is 1 out of 4, or 25%.

Answer: B. 25%

Three of the four outcomes show brown fur, but only one of the four is homozygous brown. Read whether the question asks about appearance or genotype.

Question 4 - Energy flow through a food chain

In a food chain, roughly 10% of the energy at one level is passed to the next. If the producers in an ecosystem store 20,000 kilocalories of energy, approximately how much energy reaches the secondary consumers?
  • A. 20 kcal
  • B. 200 kcal
  • C. 2,000 kcal
  • D. 10,000 kcal
Show the solution

Producers hold 20,000 kcal. The primary consumers that eat them receive about 10% of that: 2,000 kcal.

The secondary consumers eat the primary consumers, so they receive about 10% of 2,000 kcal, which is 200 kcal.

Two steps up the chain means multiplying by 0.10 twice.

Answer: B. 200 kcal

Count the arrows, not the organisms. Secondary consumers are two transfers up from the producers, so 10% gets applied twice.

Question 5 - Newton's second law

A cart with a mass of 4 kilograms accelerates at 3 meters per second squared. What net force is acting on the cart?
  • A. 0.75 N
  • B. 7 N
  • C. 12 N
  • D. 36 N
Show the solution

Newton's second law is F = ma - force equals mass times acceleration. This relationship appears on the GED formula sheet, so you do not need to memorize it.

Substitute: F = (4 kg)(3 m/s²) = 12 newtons.

Answer: C. 12 N

Choice A comes from dividing instead of multiplying. Write the formula down before you touch the calculator.

Question 6 - Conservation of mass

In a sealed container, 14 grams of a solid reactant combine completely with 32 grams of a gas to form a single product. What is the mass of the product?
  • A. 18 g
  • B. 32 g
  • C. 46 g
  • D. It cannot be determined.
Show the solution

The law of conservation of mass says matter is not created or destroyed in an ordinary chemical reaction. In a sealed container, nothing can escape, so the total mass before and after must match.

14 g + 32 g = 46 g of product.

Answer: C. 46 g

Watch for the word sealed. If a reaction releases a gas into an open beaker, the measured mass of what's left will drop - and that is the version the test likes to follow up with.

Question 7 - How metamorphic rock forms

Which combination of conditions changes an existing sedimentary rock into a metamorphic rock?
  • A. Cooling and crystallization of molten material
  • B. Weathering followed by compaction of loose particles
  • C. Intense heat and pressure without complete melting
  • D. Evaporation of mineral-rich water
Show the solution

Metamorphic rock is existing rock that has been reworked. Heat and pressure deep in the crust rearrange the minerals and change the rock's texture, but the rock never fully melts - if it did, it would cool into igneous rock instead.

Choice A describes igneous rock. Choices B and D both describe ways sedimentary rock forms.

Answer: C. Intense heat and pressure without complete melting

The whole rock cycle turns on three verbs: melt and cool (igneous), settle and compact (sedimentary), squeeze and heat (metamorphic).

Question 8 - Drawing a conclusion from data

A student grew four identical bean plants under the same light, water and soil conditions, changing only the amount of fertilizer. After 30 days she recorded the height of each plant.
Fertilizer (g/week)Height after 30 days (cm)
014
221
427
619
Which conclusion is best supported by the data?
  • A. Fertilizer has no measurable effect on plant height.
  • B. More fertilizer always produces taller plants.
  • C. Plant height increases with fertilizer up to a point, then declines.
  • D. The plants would have grown taller with more sunlight.
Show the solution

Read the trend, not just the endpoints. Height climbs from 14 to 21 to 27 cm as fertilizer goes from 0 to 4 grams, then drops to 19 cm at 6 grams.

Choice A contradicts the numbers. Choice B is broken by that last row. Choice D talks about sunlight, which was held constant and never tested - the data cannot support any claim about it.

Choice C is the only statement the table actually demonstrates.

Answer: C. Plant height increases with fertilizer up to a point, then declines.

On data questions, eliminate anything the experiment did not measure. That single habit removes one or two choices on almost every item.

Bringing it together

Notice how few of these needed memorized facts. You needed to know what a mitochondrion does, that energy drops about 90% per level, that F = ma sits on the formula sheet, and that sealed means nothing escapes - then the rest was careful reading. Build that habit and the Science test stops feeling like a memory contest. Score 145 or better here and this subject is done.

Keep practicing

Want a full set of GED practice?

Our downloadable GED practice pack covers all four subjects - Language Arts, Math, Science and Social Studies - with a worked explanation behind every answer. Start with the free sample, then grab the complete pack.

Prefer the complete set? The full GED practice tests covering all four subjects are on Udemy with worked visuals for every question.

Frequently asked questions

How long is the GED Science test and how many questions does it have?
You get 90 minutes with no break, and most forms run about 34 to 40 items. An on-screen TI-30XS calculator is available throughout, and you may bring your own TI-30XS to a test center. Question types include multiple choice, drag-and-drop, drop-down, fill-in-the-blank and select-an-area.
What science topics does the GED actually cover?
Life science is about 40% - cells, body systems, heredity, evolution and ecosystems. Physical science is another 40% - motion, forces, energy, and basic chemistry. Earth and space science makes up the remaining 20%, covering Earth's structure, weather and climate, and the solar system.
Do I need to memorize science formulas for the GED?
Very few. A reference sheet is provided on-screen and covers the common physical science relationships. What you do need is fluency reading passages, charts, diagrams and data tables, because most items give you the information and test whether you can reason from it.

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