GED Life Science Practice Questions, Set 3

1.In a pond food web, frogs eat insects, and both snakes and herons eat frogs. A disease kills most of the frogs in one summer. What is the most likely short-term result?

1. A.Insects decline because fewer frogs pollinate plants
2. B.Insects increase, and snakes and herons lose food
3. C.Snakes and herons gain food, and insects decline
4. D.Herons switch to eating plants, and snakes leave

2.A bear eats berries in late summer and also catches salmon that eat smaller fish. Which statement correctly describes the bear’s place in the food web?

1. A.It is only a primary consumer since it eats some plants
2. B.It is a producer because it eats berries made by plants
3. C.It is a decomposer because it feeds on other animals
4. D.It is a primary consumer and also a higher-level consumer

3.A student fills two jars with the same moist fallen leaves. Jar 1 is heated in an oven to kill all microbes, then both jars are sealed. After two months, the leaves in Jar 2 have mostly broken down, while the leaves in Jar 1 look almost unchanged. What does this result show?

1. A.Sealed jars prevent leaves from ever breaking down
2. B.Heat speeds up the breakdown of dead leaves
3. C.Living microbes are needed to break down dead leaves
4. D.Fallen leaves contain no nutrients for other living things

4.A community garden has many aphids on its plants each spring. The gardeners release ladybugs, which eat aphids. What is the most likely effect on the aphid population over the next few weeks?

1. A.It increases because ladybugs protect the plants
2. B.It decreases because predators eat more aphids
3. C.It stays the same because aphids eat only plants
4. D.It increases because ladybugs add food to the soil

5.A new highway cuts a forest in two. A population of salamanders is split into two smaller groups that cannot cross the road. Which problem are the smaller groups most likely to face over time?

1. A.They will each grow larger than the original population
2. B.They will quickly turn into two new species within a year
3. C.They will be at greater risk from disease or a bad season
4. D.They will no longer need food, water or shelter to survive

6.Bald eagle nesting pairs in the lower 48 states fell to about 400 by the early 1960s. The pesticide DDT made eggshells so thin that they broke during nesting. After DDT was banned in 1972, nesting pairs rose to many thousands. Which statement best explains the recovery?

1. A.More eggs survived to hatch once DDT was gone
2. B.Eagles began laying eggs with no shells at all
3. C.More eagles were hunted after DDT was removed
4. D.Eagles learned to build stronger nests after 1972

7.A home thermostat turns the furnace on when the room drops below 68°F and turns it off when the room rises above 68°F. Which body process works in the most similar way?

1. A.Muscles grow larger after weeks of regular weight training
2. B.A cut finger heals and forms new skin over several days
3. C.Food moves through the stomach and then the small intestine
4. D.Sweating starts when the body heats up and stops as it cools

8.A health fair poster lists four conditions. Which one is caused by a pathogen and can spread from person to person?

1. A.Strep throat, caused by bacteria
2. B.Sickle cell disease, caused by a gene
3. C.Lung cancer linked to smoking
4. D.Scurvy, caused by too little vitamin C

9.During an infection, the brain raises the body’s temperature set point, and a fever develops. Many bacteria and viruses reproduce more slowly at higher temperatures. What is the most likely role of a moderate fever?

1. A.It cools the blood so the immune system can rest
2. B.It shows that homeostasis has completely stopped working
3. C.It kills body cells so that the pathogen has no food
4. D.It helps the body slow the growth of the pathogen

10.A lifeboat guide warns sailors never to drink seawater, even when very thirsty. Seawater is much saltier than blood, and the kidneys must use extra water from the body to flush out the extra salt. What happens to a person who drinks seawater?

1. A.Blood becomes less salty than it was before
2. B.The body loses more water than the person drank
3. C.The kidneys stop working until all the salt is gone
4. D.The salt replaces the water the body has lost

11.A pet store worker measures dissolved oxygen in a tank full of water plants and fish. 4 p.m. (lights on all day): 9.0 mg/L 4 a.m. (lights off all night): 5.5 mg/L Why is the oxygen level lower at 4 a.m.?

1. A.Fish stop breathing while the lights are off at night
2. B.Plants make extra oxygen in the dark to store for later
3. C.Water holds more oxygen when the tank is dark
4. D.Plants and fish use oxygen, but no photosynthesis occurs

12.Bromothymol blue turns yellow when carbon dioxide builds up in water and stays blue when it does not. A student sets up three sealed tubes in bright light. Tube 1: water plant only, stays blue Tube 2: snail only, turns yellow Tube 3: water plant and snail, stays blue What does Tube 3 show?

1. A.The snail stopped breathing when the plant was added
2. B.Snails and plants both add carbon dioxide in light
3. C.The plant used the carbon dioxide that the snail made
4. D.The plant made carbon dioxide faster than the snail

13.A researcher measures how fast a plant takes in carbon dioxide at different light levels, keeping temperature and CO₂ level the same. 100 units of light: 4 units of CO₂ per hour 200 units: 8 400 units: 14 800 units: 15 Which conclusion is best supported?

1. A.Doubling the light always doubles the rate of photosynthesis
2. B.The plant stops photosynthesis when light goes above 400 units
3. C.Carbon dioxide uptake falls as light goes up past 200 units
4. D.Above about 400 units, something besides light limits the rate

14.A roofer spends years working in strong sunlight, and a mutation forms in the DNA of some skin cells on the back of the neck. Can this mutation be passed to the roofer’s future children?

1. A.No, because sunlight can never change any DNA
2. B.Yes, because every mutation in the body is inherited
3. C.Yes, because skin cells make the egg and sperm cells
4. D.No, because it is not in the egg or sperm cells

15.A health article notes that adult height in a population does not fall into just two groups, tall and short. Instead, heights form a smooth range from very short to very tall. Which explanation best fits this pattern?

1. A.Height depends only on the food a person eats
2. B.Height is shaped by many genes and the environment
3. C.Height is decided by the genes of the father only
4. D.Height is set by one gene with two alleles

16.Huntington’s disease is caused by a dominant allele (H). A man with genotype Hh and a woman with genotype hh plan to have a child. What is the chance that the child inherits the disease allele?

1. A.0%
2. B.25%
3. C.50%
4. D.100%

17.Fruit flies are often used in genetics labs. A normal body cell of a fruit fly has 8 chromosomes. How many chromosomes are in a fruit fly egg cell made by meiosis?

1. A.4
2. B.16
3. C.8
4. D.2

18.A purple-flowered pea plant could have genotype PP or Pp. A breeder crosses it with a white-flowered plant (pp). All 60 offspring have purple flowers. What is the most likely genotype of the purple parent?

1. A.Pp, since half of the offspring were purple
2. B.PP, since no white offspring appeared
3. C.Pp, since purple is the dominant color
4. D.pp, since it was crossed with a white plant

19.The harmless scarlet king snake has red, black and yellow bands that look much like those of the venomous coral snake, which lives in the same area. Predators that learn to avoid coral snakes also tend to avoid king snakes. How did the king snake’s coloring most likely become common?

1. A.Predators taught young king snakes which colors to grow
2. B.Banded king snakes were eaten less and left more young
3. C.King snakes copied the colors after seeing coral snakes
4. D.Coral snake venom changed the color genes of king snakes

20.In a long-running lab study, scientists grew 12 populations of the same bacteria for over 30,000 generations. Around generation 31,000, one population began using a food source the others could not use. Tests traced the change to new mutations. What does this study show?

1. A.Bacteria decide which new traits they will need later
2. B.All 12 populations should have changed in the same way
3. C.Mutations can supply new traits that selection acts on
4. D.New traits appear only when scientists add new genes

21.A museum displays a fossil called Archaeopteryx. It had feathers and wings like a bird, but also teeth, clawed fingers and a long bony tail like a small reptile. Why do scientists consider this fossil important?

1. A.It proves that modern birds still have teeth
2. B.It proves that feathers first evolved for flying
3. C.It shows that birds lived before all reptiles
4. D.It shows features linking reptiles and birds

22.Hunting reduced northern elephant seals to about 20 animals in the 1890s. After protection, the population grew to over 200,000, but today’s seals have very little genetic variation. Why is the low variation a concern for the species?

1. A.Hunters will be able to find the seals more easily
2. B.The seals will be unable to produce any young
3. C.The seals can no longer find enough food to eat
4. D.A new disease could harm nearly all of the seals

23.Blood arriving at the muscles has a high level of oxygen, and the muscle cells have a low level because they use oxygen quickly. Which way does oxygen move, and by what process?

1. A.From blood into cells, by diffusion
2. B.From cells into blood, by diffusion
3. C.From cells into blood, by active transport
4. D.From blood into cells, by photosynthesis

24.In the 1850s, a scientist named Rudolf Virchow wrote that every cell comes from a cell that already exists. He based this on many microscope observations. Which observation would best support his idea?

1. A.Cells are seen splitting in two to form new cells
2. B.Cells are made mostly of water and dissolved salts
3. C.Dead cells break down when they are left in water
4. D.Plant and animal cells are about the same size

25.The enzyme lactase breaks down lactose, the sugar in milk. A lab adds lactase to a cup of lactose solution and to a cup of sucrose (table sugar) solution. Only the lactose is broken down. Which idea does this result support?

1. A.Lactase breaks down every kind of sugar
2. B.Sucrose is not a sugar found in living things
3. C.Each enzyme works on a specific substance
4. D.Enzymes are used up after one reaction

26.A health class learns that a cold virus has genetic material inside a protein coat but has no cell membrane, no ribosomes and no way to make energy. It can make copies of itself only inside a host cell. Why do many biologists say viruses are not living cells?

1. A.Viruses are too small to cause any illness
2. B.Viruses cannot reproduce on their own
3. C.Viruses can only infect bacteria, not people
4. D.Viruses contain no genetic material of any kind

27.A houseplant is not watered for a week, and its leaves droop. Each plant cell has a large central vacuole that stores water and presses outward against the cell wall. Why do the leaves droop?

1. A.The vacuoles lose water and press less on the walls
2. B.The cell walls dissolve when the soil dries
3. C.The chloroplasts swell up and burst the cells
4. D.The cells divide too fast and stretch the leaves