GED Science Practice Test 2020 (Question Answers) PDF

GED Science Practice Test 2020 (Question Answers) PDF. Download printable and editable GED science test free pdf. This sample test includes Science Experiments, Reading, Meaning Numbers, and Graphics in Science. Our practice test will help you to make better GED Test Prep 2020 online.

NOW IT’S time to put all that you have learned about science and scientific inquiry into practice. In the following section, you will find 35
multiple-choice questions like those you will find on the GED Science Exam.

GED Science Practice Test

The good thing about multiple-choice questions is that the answer is right in front of you. All you need to do is find it, or at least eliminate some of the clearly wrong choices.

At times, you may not be able to eliminate all four of the incorrect choices. But there is no penalty for guessing on the GED. If you can eliminate one of the wrong choices, you will have a 25% chance of guessing correctly, and that is still better than leaving it blank. If you can eliminate three choices, you have a 50% chance of getting the question right.

GED Science Practice Test Question Answers

Q1. In an acid base reaction, an acid reacts with a base to produce water and a salt. The pH scale can be used to describe the acidity of a liquid. Look at the diagram below.

Which two liquids could undergo an acid base reaction?

  • A). bleach and ammonia
  • B). lye and ammonia
  • C). blood and saliva
  • D). bleach and vinegar
  • E). stomach acid and beer
View Correct Answer
 Answer: D

It is the only pair of liquids listed in which one is acidic (vinegar—pH 3) and the other basic (bleach—pH 9).

Q2. According to Newton’s laws of motion, an object set in motion remains in motion unless a force acts on it. If you suspend an object from a string and make it swing, the object will swing for a while, then slow down and stop. Why does the suspended object stop swinging?

  • A). because an object at rest remains at rest unless a force acts upon it
  • B). because the mass of the object is too small to maintain the motion
  • C). because energy is the ability to do work
  • D). because gravity is pulling it toward the Earth
  • E). because energy of motion is converted to heat through friction with air
View Correct Answer
 Answer: E

The object set in motion slows down and stops swinging because the force of friction acts on it. The kinetic energy of the object is converted to heat energy through friction with air. Statements a, c, and d are true but are not the reason why the object stops swinging. An object having any mass can maintain motion, so the statement in choice b is wrong.

Q3. In an exothermic process, heat is released by the process to the surroundings. An example of an exothermic process is burning wood. An endothermic process requires the input of heat from the surroundings. An example of an endothermic process is boiling water. Which of the following is an endothermic process?

  • A). detonation of an explosive
  • B). melting ice
  • C). burning paper
  • D). the formation of helium on the sun
  • E). freezing water
View Correct Answer
 Answer: B

An endothermic process requires the input of heat energy. The only one that requires input of energy (heat) is melting ice (ice melts when
heated). The rest of the processes listed give off heat, so they are exothermic.

Q4. Ice floats on water because

  • A). ice is less dense than water
  • B). water conducts heat better than ice
  • C). ice has a lower temperature.
  • D). heat from the Earth’s core travels upward, cooling the bottom first.
  • E). it needs energy from the sun to melt.
View Correct Answer
 Answer: A

Things that float are less dense than the substance in which they float.

Q5. Which of the following is NOT true about gravity?

  • A). The more massive two objects are, the greater the gravitational force between them.
  • B). Gravitational force between two objects depends only on the mass of the larger object.
  • C). Gravitational force between two objects depends on the distance between them.
  • D). People can jump higher on the moon than on Earth because the gravitational force between a person and the moon is lower than the gravitational force between a person and the Earth.
  • E). A gravitational force exists between the moon and the sun.
View Correct Answer
 Answer: B

The statement is false because the gravitational force between two objects depends on the masses of both objects. All the other statements
are true and consistent with Newton’s Law of Gravitation.

Q6. Change of phase is a process whereby matter changes form (solid, liquid, gas). Which one of the following constitutes a phase change?

  • A). condensation of water vapor
  • B). photosynthesis
  • C). digestion of food
  • D). dry-cleaning
  • E). exhaling
View Correct Answer
 Answer: A

When water vapor condenses, gas changes to liquid. Choices b, c, and d involve chemical reactions and can’t be considered physical processes. Through exhaling, choice e, air is pushed out of the lungs, but there is no phase change.

Q7. Two negatively charged spheres

  • A). repel each other.
  • B). attract each other.
  • C). neither attract nor repel each other.
  • D). can either attract or repel each other depending on their position.
  • E). attract each other only when the distance between them is small.
View Correct Answer
 Answer: A

Two like charges always repel.

Q8. Which statement about energy and/or matter is incorrect?

  • A). Matter and energy can’t be destroyed.
  • B). Matter and energy can’t be created.
  • C). All matter tends toward more disordered states.
  • D). Energy can be stored and transferred.
  • E). Heat energy is composed of heat atoms.
View Correct Answer
 Answer: E

The statement is false because energy is not composed of matter (atoms). All other statements are true.

Q9. The boiling point in hydrocarbons (molecules containing H and C) increases with increasing molecular weight due to larger intermolecular forces. Which of these hydrocarbons would you expect to have the highest boiling point?

View Correct Answer
 Answer: E

The molecule in choice e has the most atoms and the largest molecular weight. It therefore has the highest boiling point.

Q10. People wear woolen gloves in the winter because gloves

  • A). generate heat energy through radiation.
  • B). increase the temperature of cold air through convection.
  • C). decrease the loss of body heat to surroundings through insulation.
  • D). increase the amount of heat energy generated by the body through conduction.
  • E). transform cold wind energy into thermal energy.
View Correct Answer
 Answer: C

Gloves provide insulation. They can’t generate heat, choice a. Gloves left out in the snow would be cold. Gloves can’t have an effect on the temperature, choice b. They also don’t affect the amount of energy your body produces, choice d, or transform energy in any way, choice e.

Q11. Different colors of light correspond to different wavelengths. Wavelengths are often quoted in nanometers (nm). The wavelengths of the visible part of the spectrum are shown in the diagram below.

According to the diagram, blue-green light would most likely have a wavelength of

  • A). 670 nm.
  • B). 550 nm.
  • C). 350 nm.
  • D). 470 nm.
  • E). 700 nm.
View Correct Answer
 Answer: D

The wavelength of blue-green should be between the wavelength of blue light and green light. The wavelength of blue light is about 450
nm and the wavelength of green light is at about 500 nm.Midway between these wavelengths is 470 nm.

Q12. What always stays the same when a chemical reaction takes place?

  • A). the number of atoms
  • B). the number of molecules
  • C). the amount of gas
  • D). the amount of solid matter
  • E). the amount of disorder
View Correct Answer
 Answer: A

The number of atoms stays constant throughout a chemical reaction. The number of molecules can change (choice b). For example, in  photosynthesis, 6 molecules of carbon dioxide and 6 molecules of water (total 12 molecules) can react to form 1 molecule of glucose and 6 molecules of oxygen (total of 7 molecules). Similarly, the amount of gas and solid can change (choices c and d). The amount of disorder in the universe is always increasing, so it does not have to stay constant through a reaction (choice e).

Q13. Which of the following is NOT true about sunlight?

  • A). It is a form of radiation.
  • B). It is used as an energy source in solar-powered calculators
  • C). It contains the colors of the rainbow.
  • D). Its speed is infinite.
  • E). It can be absorbed by plants.
View Correct Answer
 Answer: D

The statement is false because light has a finite speed. It is very large, but it is not infinite. The rest of the statements are true.

Q14. In order to protect themselves from being eaten, animals resort to camouflage and chemical defense. Animals camouflage by mimicking the appearance of their environment. Animals that have chemical defenses contain chemicals noxious to predators. Which of these is NOT an example of camouflage or chemical defense?

  • A). A walking stick insect looks just like a twig.
  • B). A skunk has an awful smell.
  • C). Feathers of the pitohui bird in New Guinea contain a deadly toxin.
  • D). Roses have thorns.
  • E). A harlequin crab looks just like the sea cucumber it lives on.
View Correct Answer
 Answer: D

Thorns are a form of defense, but are neither camouflage nor chemical defense. Choices a and e are examples of camouflage. Choices b
and c are examples of chemical defense.

Q15. Osmosis is the movement of water across a selectively permeable membrane in order to equalize the concentration (the amount of protein per milliliter of water) on two sides of the membrane. Consider the diagram below. The container is divided into two compartments, A and B, by a selectively permeable membrane. Each circle represents 100 protein molecules that can’t pass through the membrane. The amount of water on two sides of the membrane is initially equal. What will happen as a result of osmosis?

  • A). Protein will flow from compartment B to compartment A.
  • B). Protein will flow from compartment A to compartment B.
  • C). Water will flow from compartment B to compartment A.
  • D). Water will flow from compartment A to compartment B.
  • E). Both water and protein will flow from compartment B to compartment A.
View Correct Answer
 Answer: D

The concentration of protein in compartment B is higher. Because of the nature of the membrane, the protein can’t pass through it. The
only way for concentration to reach the same level in two compartments is for water to flow from A to B.

Q16. Which of the following statements about human genetics is true?

  • A). Half the chromosomes in a human are inherited from the mother, and half from the father.
  • B). A human looks 50% like the father, and 50% like the mother.
  • C). Fraternal twins are genetically more similar than siblings who are not twins.
  • D). Exposure to X-rays can have no effect on a human’s chromosomes.
  • E). Genes are particles found in the nucleus of DNA atom.
View Correct Answer
 Answer: A

Every human normally inherits 23 chromosomes from the mother and 23 chromosomes from the father. However, that doesn’t mean that
humans look exactly 50% like the father and 50% like the mother (choice b), since one parent’s genes can be more dominant, and since
genes from two parents sometimes produce a blended effect. Fraternal twins happen to be in the womb at the same time, but genetically, they are not any more similar than two siblings who are not twins (choice c). Fraternal twins come from two different eggs fertilized by two different sperm cells. Exposure to X-rays can alter chromosomes (choice d). Genes are not particles. DNA is not an atom and it doesn’t have a
nucleus (choice e). Genes are found in the nucleus of a cell and are made of DNA.

Q17. Identical twins have exactly the same genes. Identical twins result when

  • A). an egg fertilized by one sperm divides in two.
  • B). two eggs are fertilized with two sperm cells.
  • C). one egg divides in two and is fertilized by two sperm cells.
  • D). the same sperm cell fertilizes two eggs.
  • E). the same egg is fertilized by two sperm cells.
View Correct Answer
 Answer: A

In order for twins to have the same genes, they need to come from one egg and one sperm cell.

Q18. In peas, the gene for green color is dominant over the gene for yellow color. We will specify the gene for yellow peas as y, and the gene for green peas as Y. Each pea has two genes for color (one from each parent) and donates only one gene for color to its offspring. Yellow peas have the genotype yy. Any other genotype leads to green peas. Consider the following Punnett square:

The offspring of these two parents

  • A). could never be yellow.
  • B). could never be green.
  • C). could be either green or yellow.
  • D). could be yellow-green.
  • E). could be yellow, but could never have yellow offspring.
View Correct Answer
 Answer: C

According to the Punnett square, the combination of genes of Parent I with the genes of Parent II results in either offspring with yy (which
is yellow) or Yy (which is green).

Q19. Which of the following is NOT true?

  • A). All organisms are made of atoms.
  • B). All organisms are made of molecules.
  • C). All organisms are made of one or more cells.
  • D). All organisms have genetic material.
  • E). All organisms have a cell wall.
View Correct Answer
 Answer: E

The statement is false. Animal cells usually don’t have a cell wall. Other statements are true.

Q20. In humans, a pair of chromosomes (one from each parent) determines the sex of the baby. Females have two X chromosomes, while males have an X and a Y chromosome. The baby always gets an X chromosome from the mother, so in humans, the father determines the sex of the baby by supplying it with either an X chromosome to make it female, or a Y chromosome to make it male. In birds, like in humans, a pair of chromosomes determines the sex. Birds with two W chromosomes are male. Birds with a W chromosome and a Z chromosome are female. Which statement is true about birds?

  • A). The male bird determines the sex of the offspring by supplying it with the W or the Z chromosome.
  • B). The male bird determines the sex of the offspring by supplying it with one of its W chromosomes.
  • C). The male bird determines the sex of the offspring by supplying it with the X or the Y chromosome.
  • D). The female bird determines the sex of the offspring by supplying it with the X or the Y chromosome.
  • E). The female bird determines the sex of the offspring by supplying it with the W or the Z chromosome.
View Correct Answer
 Answer: E

In humans, the sperm determines the sex of the child because the male has two different chromosomes. In birds, the female has two different
chromosomes, so she determines the sex of the offspring. Birds have Ws and Zs, not Xs and Ys like humans, so choice d is incorrect.

Q21. A species may live in association with another species. Such an arrangement is called symbiosis. Symbiosis in which both species benefit is called mutualism. If the symbiosis is beneficial to one species and neither beneficial nor harmful to the other, it is called commensalism. If one species benefits at the expense of the other, the relationship is called parasitism. A tick that attaches to the skin of a human or animal and feeds on its blood is an example of

  • A). commensalisms.
  • B). parasitism
  • C). competition.
  • D). coevolution.
  • E). mutualism.
View Correct Answer
 Answer: B
The tick is a parasite. It benefits, while the animal it feeds from suffers.

[Reading for Meaning in Science] Questions 22 through 24 are based on the following passage.

An island in the Adriatic Sea was overpopulated with snakes. Sailors who came to the island brought and let loose mongoose, animals that feed on snakes. The population of snakes started decreasing since the mongooses were eating them. The mongoose population started increasing since there was ample food around. The mongooses were not native to the island and there was no predator on the island to keep the mongoose population in check. At some point, there were hardly any snakes left on the island, and people started populating it. The
mongoose, facing a shortage of snakes, started eating chickens that people kept for their eggs and meat. However, people caught on and protected the chickens from getting eaten. The mongoose population decreased. Some remain on the island, but their number is now at equilibrium, kept in check by the availability of food.

Q22. The passage illustrates

  • A). the interdependence of organisms.
  • B). the fragility of an ecosystem.
  • C). the ability of humans to change an ecosystem.
  • D). the relationship between the population of predator and prey.
  • E). . all of the above.
View Correct Answer
 Answer:  E

Statements a through d were illustrated in the passage. Mongooses depend on snakes for food, choice a. The balance in the ecosystem was disturbed when a new predator was introduced, choice b. Humans entirely changed the ecosystem when they brought the mongooses, choice
c.When the population of mongooses increased, the population of snakes decreased, causing a drop in the population of mongooses, choice d.

Q23. There were hardly any snakes left on the island because

  • A). mongooses had eaten them.
  • B). people had killed them.
  • C). there was no predator for the mongooses.
  • D). sailors brought them prey
  • E). the chickens didn’t taste as good to the mongooses.
View Correct Answer
 Answer: A

There was no mention of choice b in the passage. Choice c is true, but not as directly related to snake disappearance as choice a. Choice d is
false. Sailors did not bring prey for the snakes; they brought a predator. There isn’t enough information to support choice e, and even if it
were true, it wouldn’t be directly related to the disappearance of snakes.

Q24. Which statement best describes the change in the population of mongooses on the island?

  • A). The population was zero before sailors brought a few. The few then multiplied, and the number of mongooses on the island is still
    steadily growing.
  • B). The population was zero before sailors brought a few. The few then multiplied, increasing the number of mongooses. When
    the snakes were almost gone, the mongoose population started decreasing.
  • C). The population was small before sailors brought more mongooses, increasing the gene pool. The number of mongooses kept growing until the people started protecting the chickens.
  • D). The population was small before sailors brought more snakes, increasing the food supply for the mongoose. The number of mongooses kept growing until the snake population was almost gone. The mongooses died out since they ran out of food.
  • E). The population was initially large, but when a predator was brought by sailors, the number of mongooses decreased.
View Correct Answer
 Answer: B
There is no support for other statements in the passage.

Q25. There are four blood types in humans: A, B, AB, and O. An individual with blood type A has antibodies for B, so he or she can’t receive type B blood. Similarly, a person with blood type B has antibodies for type A and can’t receive type A
blood. A person with AB blood type has no antibodies and can receive blood from anyone. A person with type O blood has both A and B antibodies and can receive blood only from someone else with type O blood. Based on this information, someone with type B blood can donate to

  • A). blood groups B and O
  • B). blood groups B and AB
  • C). only blood group B
  • D). only blood group AB
  • E). only blood group O
View Correct Answer
 Answer: B

Someone who has blood type B can donate blood to those who don’t have antibodies for B. These include other people with type B blood
(they have antibodies for A only) and those with type AB blood (they don’t have any antibodies).

Q26. Two main chemicals are responsible for the communication of the brain with the organs you have no conscious control over (heart, digestive system, endocrine system). The chemical norepinephrine helps your body get ready for a fightor-flight action by stirring up energy stores. In contrast, the chemical acetylcholine helps conserve energy by slowing the heart and increasing intestinal absorption. Which of the following situations is least likely to lead to increased levels of norepinephrine?

  • A). being chased by a flesh-eating animal
  • B). running away from someone holding a knife
  • C). petting a rabbit
  • D). taking an important exam
  • E). going on a first date with someone
View Correct Answer
 Answer: C
Levels of norepinephrine rise when there is a potential for danger, stress, or excitement. Choice c, petting a rabbit, is the only choice
that would tend to calm, rather than scare or excite, a person.

Q27. Most bacteria cannot grow in high concentrations of salt. As a result,

  • A). salt acts as a preservative in ham, beef jerky, and other salty foods.
  • B). people who don’t eat enough salt become anemic.
  • C). Utah’s great Salt Lake is filled with bacteria.
  • D). most antibiotics are sweet.
  • E). there are no bacteria in fresh water.
View Correct Answer
 Answer: A
Salty foods are less prone to bacterial attack because most bacteria can’t grow in environments that are too salty. Being anemic (choice b)
is not related to bacteria. Choice c is inconsistent with the question. Choices d and e are not true and are inconsistent with the question.

Q28. In the early 19th century, almost all peppered moths collected by biologists in the U.K. were pale and mottled. Only rarely was a collector able to find a dark-peppered moth. After the Industrial Revolution, when furnaces filled the air with dark soot, the light-peppered moth became rare and the dark-peppered moth was most common in industrial cities. A reasonable explanation for this change is that the dark moth was less likely to be seen and eaten by birds against the dark background. This explanation illustrates the principle of

  • A). conservation of energy.
  • B). natural selection.
  • C). gene flow.
  • D). male competition.
  • E). acquired traits.
View Correct Answer
 Answer: B
Natural selection is the process whereby the members of the species who are best able to survive and reproduce in an environment thrive,
passing their genes on to next generations. The pollution in the environment selected for darkness in peppered moths.

Q29. All of the following are mammals EXCEPT 

  • A). humans.
  • B). rabbits.
  • C). whales.
  • D). penguins.
  • E). rats.
View Correct Answer
 Answer: D
Penguins are birds. They hatch from eggs and have wings. They are not mammals; they don’t give birth or breastfeed their young.

Q30. All of the following are primates EXCEPT

  • A). humans.
  • B). gorillas.
  • C). whales.
  • D). chimpanzees.
  • E). orangutans.
View Correct Answer
 Answer: C

Whales are not primates. Primates have five digits on each hand and foot, binocular vision, and flexible shoulder joints.

Q31. A woman is most likely to get pregnant if she has unprotected sex a few days before and on the day of ovulation, when the egg is released from the ovaries. The release of the egg is hormonally stimulated, meaning that a hormone in the woman’s body triggers ovulation. On average, women ovulate around the 14th day of their menstrual cycle. The following is a graph showing the levels of three hormones throughout the menstrual cycle of an average woman. 

Based on the graph, which hormone is most directly responsible for triggering ovulation?

  • A). FSH
  • B). LH
  • C). progesterone
  • D). testosterone
  • E). cholesterol
View Correct Answer
 Answer: B

The graph shows that the level of LH rapidly rises right before the 14th day of the cycle, and then falls.

Q32. As the pressure of a gas increases at a constant temperature, the volume of the gas decreases.

If you were a diver and you wanted to take an oxygen tank with you, what would you do?

  • A). Pressurize the oxygen, so more of it can fit in a tank of a manageable size.
  • B). Decrease the pressure of oxygen in the tank, so the tank doesn’t explode.
  • C). Increase the temperature of oxygen in the tank, so that the cold oxygen doesn’t damage the lungs.
  • D). Decrease the temperature of oxygen, so that it doesn’t escape from the tank.
  • E). Increase the temperature of the oxygen and decrease the pressure, so the volume stays the same.
View Correct Answer
 Answer: A

A diver would want to take a lot of oxygen without letting the tank get too bulky. Other choices are either false (choices d and e) or not a major concern (choices b and c).

Q33. The amount of solute that can be dissolved in a solvent at a given temperature is called solubility. For most substances, solubility increases with temperature. Rock candy can be made from sugar solutions that have an excess of sugar dissolved. The amount of sugar per 100 grams of water at a given temperature has to be higher than the amount that is normally soluble in order to make rock candy. Based on the solubility of sugar in water as a function of temperature, plotted in the graph, how much sugar would you need to dissolve in 100 grams of water to make rock candy at 40° C?

  • A). less than 50 grams
  • B). between 50 and 100 grams
  • C). between 100 and 150 grams
  • D). . between 150 and 200 grams
  • E). more than 250 grams
View Correct Answer
 Answer: E

According to the graph, at 40° C, about 250 grams of sugar can be normally dissolved in 100 grams of water. In order to make rock candy,
this amount has to be exceeded.

Questions 34 and 35 are based on the following passage.

In 1628, English physician William Harvey established that the blood circulates throughout the body. He recognized that the heart acts as a pump and does not work by using up blood as earlier anatomists thought. To carefully observe the beating of the heart and the direction of blood flow, Harvey needed to see the works of the blood in slow motion. Since there was no way for him to observe a human heart in slow
motion, he studied the hearts of toads and snakes, rather than the rapidly beating hearts of “warm-blooded” mammals and birds. By keeping these animals cool, he could slow their hearts down. The main argument for his conclusion that the blood circulates stemmed from his measurement of the amount of blood pumped with each heartbeat. He calculated that the amount of blood pumped each hour by far exceeds the total amount of blood in the body and proved that the same blood passes through the heart over and over again.

Q34. What misconception did scientists harbor before Harvey’s study?

  • A). The heart circulates blood.
  • B). The heart pumps blood.
  • C). The heart uses up blood.
  • D). The heart contains no blood.
  • E). The heart of birds beats faster than the heart of frogs.
View Correct Answer
 Answer: C

The passage explained that other scientists at the time mistakenly thought that the heart uses up blood. Choices a, b, and e are not  misconceptions. Choice d was not mentioned in the passage.

Q35. Which of the following did Harvey do?
I. Observe the heartbeat and blood flow in snakes and frogs.
II. Determine that the heart acts as a pump.
III. Count the number of blood cells that pass through the heart every hour.
IV. Show that the blood circulates.

  • A). He did only I.
  • B). He did I and II.
  • C). He did I, II, and IV.
  • D). He did I, III, and IV.
  • E). He did II, III, and IV.
View Correct Answer
 Answer: D

The passage explained that Harvey did I, II, and IV. Although he also calculated the amount of blood that passes through the heart every hour, he did not count the blood cells one by one (III), nor did he have the technology to do that. 

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