Middle school life science practice test: free questions with answers

The daily Grade 8 Life Science paper has 8 original questions worth 25 to 35 marks. It covers cells and microscopes, photosynthesis and respiration, food chains and ecosystems, inheritance and variation, the heart, digestion, health and disease, and human impact on the environment, which is a close match for middle school life science.

If your school teaches integrated science instead, the life science content is the same, and the 8th grade physical science practice test covers the physics and chemistry side.

What's on a middle school life science test

Courses differ by state. In states that use the Next Generation Science Standards (NGSS), middle school life science has four parts:

• Cells and organisms: living things are made of cells, the parts of a cell each do a job, and the body is a system of interacting subsystems.
• Ecosystems: how organisms interact, and how energy and matter move through food webs.
• Heredity: how genes pass from parents to offspring, and how mutations can change traits.
• Evolution: evidence from fossils and anatomy, and how natural selection changes traits in a population over time.

Free life science practice test: 7 questions

We wrote these questions for this page. Give yourself 20 minutes, then check the answers below.

1. Which three structures do plant cells have that animal cells lack?
2. A microscope has a 10× eyepiece and a 40× objective lens. What is the total magnification? A cell looks 2 mm wide at that magnification. How wide is it really?
3. What does a plant take in for photosynthesis, and what does it make?
4. In a forest, foxes eat rabbits. What happens to the rabbit population, and then to the plants they eat, if the foxes disappear?
5. Why do brothers and sisters look similar but not identical?
6. A population of moths lives on dark tree bark. Explain how dark moths could become more common than pale ones over many generations.
7. How do the respiratory and circulatory systems work together to supply your muscles with oxygen?

Life science practice test answers

1. Cell wall, chloroplasts and a large permanent vacuole. The cell wall gives support, chloroplasts carry out photosynthesis, and the vacuole holds sap that keeps the cell firm. Animal and plant cells share the rest: the nucleus, the membrane around the cell, the cytoplasm inside it and the mitochondria. Look inside both in the Cell Simulator.

2. 400×, and 0.005 mm (5 μm). Multiply the two lenses: 10 × 40 = 400. Then real size = image size ÷ magnification = 2 ÷ 400 = 0.005 mm. The Magnification Calculator and Virtual Microscope let you practice this.

3. It takes in carbon dioxide and water and, using light energy captured by chlorophyll, makes glucose and oxygen. The plant uses the glucose for energy and to build new material, and releases the oxygen.

4. With no foxes, fewer rabbits are eaten, so the rabbit population grows. More rabbits eat more plants, so the plants decrease. Later, with less food, the rabbit numbers fall again. A change to one population ripples through the whole food web. Model it with the Population Growth Calculator.

5. Each child gets half of their genes from each parent, but a different mix each time. They share many genes, so they look alike, but not the same combination, so they aren't identical. Only identical twins share the same genes.

6. Moths vary in color. On dark bark, pale moths are easier for birds to see, so more of them are eaten. Dark moths survive and reproduce more, and pass the genes for dark color to their offspring. Over many generations, dark moths become more common. That is natural selection, which you can run in the Natural Selection simulator.

7. The lungs take in oxygen, which moves into the blood in the tiny air sacs. The heart pumps that oxygen-rich blood through the arteries to the muscles, where cells use the oxygen in respiration. The blood carries carbon dioxide back to the lungs to be breathed out. Try a question on body systems from our Human Physiology course, then press Mark.

Use the daily paper as a short timed practice test

1. Open today's Grade 8 Life Science paper and work to the suggested time, 30 to 35 minutes.
2. For explain questions, give a cause and its effect: "fewer foxes, so more rabbits survive".
3. Mark it with the mark scheme and note the topic behind each lost mark.
4. Fill gaps with the Cell Biology and Genetics and DNA courses.

Common life science mistakes

• Saying plants don't respire: they respire all the time, and photosynthesize only in light.
• Multiplying when you should divide to find a real size from a magnified image.
• Saying animals adapt on purpose: natural selection acts on variation that is already there.
• Following only one link in a food web question: trace the effect to every connected population.
• Thinking genes come only from one parent: half come from each.

Read next

United States · Middle school8th Grade Physical Science Practice Test With AnswersA free 8th grade physical science practice test on forces, motion, energy, waves, matter and chemical reactions, with worked answers and two daily papers.