GED practice test

GED Science Practice Test

Life, physical, and earth and space science: read data, design experiments, draw conclusions. Here are 10 GED science questions, each with the answer and the reason.

Updated 2026-11-14 by the Tigertest team. Based on the assessment targets in the GED Testing Service Assessment Guide for Educators (October 2020 edition). Original questions; not affiliated with GED Testing Service.

1. When a virus enters the body for the first time, the immune system takes several days to make antibodies that fit that virus. Some of the white blood cells that made those antibodies remain in the body for years as memory cells. If the same virus enters again, memory cells recognize it and produce antibodies within hours. A vaccine exposes the body to a harmless form or piece of a virus.

   1.

   Based on the passage, why does a vaccine help protect a person from a disease?

   • A.

     It kills any copy of the virus already in the body

   • B.

     It causes memory cells to form before the real virus arrives

   • C.

     It blocks the virus from entering the body through the nose and mouth

   • D.

     It makes antibodies that stay in the blood for life

   Answer: B.

   A vaccine gives the immune system a safe first exposure, so memory cells are ready and antibodies appear within hours of a real infection instead of days. The passage says memory cells, not the antibodies themselves, last for years, and a vaccine does not block entry or kill existing virus.

2. Cells release the energy stored in glucose through cellular respiration, a process that takes place mainly in the mitochondria. Glucose and oxygen are used up, and carbon dioxide, water and usable energy are produced. Muscle cells and nerve cells contain many more mitochondria than skin cells do.

   2.

   Which conclusion is best supported by the passage?

   • A.

     Skin cells do not carry out cellular respiration

   • B.

     Mitochondria produce the glucose that cells use

   • C.

     Cells that use more energy contain more mitochondria

   • D.

     Muscle cells need less oxygen than skin cells

   Answer: C.

   Mitochondria release energy from glucose, so cells with high energy demands, such as muscle and nerve cells, have more of them. Skin cells still have some mitochondria, glucose comes from food rather than from mitochondria, and cells with more mitochondria use more oxygen, not less.

3. 3.

   Work is done when a force moves an object, and work = force x distance. A mover pushes a crate with a force of 50 N across 4 m of floor. How much work is done on the crate?

   • A.

     12.5 J

   • B.

     46 J

   • C.

     54 J

   • D.

     200 J

   Answer: D.

   Work = 50 N x 4 m = 200 joules. Dividing gives 12.5, and adding or subtracting the two numbers does not combine a force and a distance into work.

4. Weather is the condition of the atmosphere at a particular place and time: today's temperature, wind and rain. Climate is the average pattern of weather in a place over many years, usually 30 or more.

   4.

   Which statement describes climate rather than weather?

   • A.

     Summers in the region are hot and dry, and most rain falls in winter

   • B.

     A thunderstorm dropped 3 cm of rain on the north side of the city last night

   • C.

     The high temperature today reached 35°C

   • D.

     Winds from the northwest will reach 40 km/h this afternoon

   Answer: A.

   Climate describes the long-term pattern, so a statement about typical summers and the usual rainy season is climate. A single storm, today's high and this afternoon's wind are all weather.

5. A river carries sand, silt and clay downstream. The faster the water moves, the more sediment it can carry. Where the river enters a lake or the sea, the water slows down sharply. Over time, a fan-shaped area of new land called a delta builds up at the river's mouth.

   5.

   Based on the passage, how does a delta form?

   • A.

     Waves erode the coastline and push sand up the river

   • B.

     The slowing river drops the sediment it was carrying

   • C.

     The river cuts a deeper channel through the sea floor

   • D.

     Wind piles sand into dunes at the river's mouth

   Answer: B.

   Slow water cannot carry as much sediment, so when the river slows at its mouth the sand and silt settle out and build up into a delta. This is deposition; erosion is the removal of material, which happens upstream where the water is fast.

6. In pea plants, the allele for tall stems (T) is dominant over the allele for short stems (t). A plant with the genotype Tt is crossed with another Tt plant.

   6.

   What percentage of the offspring are expected to have short stems?

   • A.

     0%

   • B.

     25%

   • C.

     50%

   • D.

     75%

   Answer: B.

   A Tt x Tt cross gives TT, Tt, Tt and tt in equal shares, and only the tt plants, one in four, are short because a single T allele makes a plant tall. 75% is the share expected to be tall.

7. A student places a sprig of a water plant in a beaker of water and sets a lamp beside it. Within minutes, small gas bubbles begin rising from the plant. When the lamp is moved farther away, bubbles rise more slowly. When the lamp is turned off, the bubbling stops.

   7.

   What is the best explanation for the bubbles?

   • A.

     The plant is releasing carbon dioxide as it breaks down stored sugar

   • B.

     Heat from the lamp is boiling the water around the plant

   • C.

     Air trapped inside the plant is escaping as the leaves warm

   • D.

     The plant is releasing oxygen as it carries out photosynthesis

   Answer: D.

   The bubbling rises and falls with the light, which is what photosynthesis needs, and oxygen is the gas it gives off. Cellular respiration releases carbon dioxide but happens with or without light, and a desk lamp does not boil a beaker of water.

8. Hydrogen gas burns in oxygen to form water. The balanced equation is 2H₂ + O₂ → 2H₂O. In a balanced equation, the number of atoms of each element is the same before and after the reaction, so 2 molecules of hydrogen and 1 molecule of oxygen always make 2 molecules of water.

   8.

   A student starts with 6 molecules of hydrogen (H₂) and 3 molecules of oxygen (O₂). If all of it reacts, how many molecules of water are formed?

   • A.

     3

   • B.

     6

   • C.

     9

   • D.

     12

   Answer: B.

   The equation shows 2 hydrogen molecules and 1 oxygen molecule make 2 water molecules, so 6 H₂ and 3 O₂ are three times that recipe and give 6 H₂O. Adding the reactant molecules, 9, or counting atoms, 12, is not what the equation says.

9. 9.

   A 5 kg cart on a smooth floor is pushed with a steady force of 20 N. Using force = mass x acceleration, what is the cart's acceleration?

   • A.

     4 m/s²

   • B.

     15 m/s²

   • C.

     25 m/s²

   • D.

     100 m/s²

   Answer: A.

   Rearranging force = mass x acceleration gives acceleration = force / mass = 20 N / 5 kg = 4 m/s². Multiplying gives 100 and subtracting gives 15; neither is a valid rearrangement of the formula.

10. Earth's outer layer is broken into large plates that move slowly, a few centimeters each year. Most earthquakes and volcanoes occur where two plates meet. Along the edges of the Pacific Ocean, a band of volcanoes and frequent earthquakes is known as the Ring of Fire.

    10.

    Based on the passage, why do earthquakes and volcanoes cluster around the Pacific Ocean?

    • A.

      The ocean water weakens the rock along the coast

    • B.

      The Pacific is the deepest ocean, so its floor is thinner and cracks easily

    • C.

      The weather is more violent over the Pacific

    • D.

      The edges of the Pacific lie along boundaries between plates

    Answer: D.

    The passage links earthquakes and volcanoes to places where plates meet, and the Ring of Fire follows the edges of the Pacific plate. Ocean depth, water and weather are not given as causes.