Earth Layers
Which Earth layer is the thinnest?
The crust
What type of rock forms when magma or lava cools and hardens?
Igneous Rock
What is a biotic factor?
A living part of an ecosystem
What organelle controls the activities of the cell?
The nucleus
What is genetic variation?
Differences in inherited traits among organisms of the same species
Which layer of Earth is liquid and helps create Earth’s magnetic field?
The outer core
What process breaks rocks into smaller pieces?
Weathering
What relationship occurs when both organisms benefit?
Mutualism
Which organelle is known as the powerhouse of the cell?
The mitochondria
Why is genetic variation important?
It helps a species survive environmental changes.
What causes movement in the mantle?
Convection currents
Which type of rock usually contains fossils?
Sedimentary rock
What level of organization includes all living and nonliving things in an area?
Ecosystem
Name one structure found in plant cells but not animal cells.
Cell wall or chloroplast
Which trait is inherited: hair color or a broken arm?
Hair color
Compare the inner core and outer core.
The inner core is solid, while the outer core is liquid. Both are made mostly of iron and nickel.
How are metamorphic rocks formed?
Existing rocks are changed by heat and pressure.
Explain why organisms compete in ecosystems.
Organisms compete because resources such as food, water, shelter, space, and sunlight are limited.
What does the cell membrane do?
It controls what enters and leaves the cell.
What could happen if a species has very little genetic variation?
The population may struggle to survive diseases or environmental changes because many individuals may be affected in the same way.
Why is Earth’s mantle important to plate movement?
Convection currents in the mantle move tectonic plates, which can cause earthquakes, volcanoes, and mountain formation.
Describe how sedimentary rock could become igneous rock.
Sedimentary rock can be buried, melt into magma, and then cool and harden into igneous rock.
A drought kills many plants in an ecosystem. Explain two effects this could have.
Herbivores may lose food, and predators may decrease because their prey populations may decrease.
Explain why chloroplasts are important to plant cells.
Chloroplasts help plants make their own food using sunlight through photosynthesis.
Explain how genetic variation can help a species survive a disease outbreak.
Some individuals may have traits that help them survive the disease. Those individuals may reproduce and pass on helpful traits.