Look and match.

landform

solar system

outer space

Match the words with their definitions.

Fill in the blanks to complete the passage.

Earth has four main : the inner core, outer core, mantle, and crust. At the center is the inner core, a solid ball of iron and nickel about 1,221 kilometers thick, with up to 5,400°C. Surrounding it is the outer core, a liquid layer 2,300 kilometers thick, also made of iron and nickel. The , the thickest layer, is 2,900 kilometers of hot molten rock. Finally, the crust is the outermost layer. On land, it is about 30 kilometers thick, while under the oceans, it is thinner, extending only about 5 kilometers from the to the mantle.

Fill in the blanks to complete the passage.

Earth's atmosphere of 78% nitrogen, 21% oxygen, and 1% other gases, such as argon, carbon dioxide, and neon. It plays an important role in both the weather we experience every day and the climate over long periods. The atmosphere also us from dangerous radiation from the Sun. Additionally, it stops most meteoroids from the ground by burning them up in the sky. These burning meteoroids are called , and we can often see them at night before they disappear. This layer is essential for life on Earth.

Fill in the blanks to complete the passage.

Earth's global ocean covers about 70% of the planet's and holds 97% of its water. The average of the ocean is about 4 kilometers. Most of Earth's volcanoes are under the oceans, including Mauna Kea in Hawaii, which is taller than Mount Everest but mostly underwater. The longest mountain range on Earth is also , located in the Arctic and Atlantic oceans. This is four times longer than the Andes, Rockies, and Himalayas combined, making it the largest mountain on the planet.

__________ is causing ice caps to melt and sea levels to rise.

Earth has many different __________, such as mountains, valleys, and deserts.

Satellites __________ Earth to help us with communication and weather forecasts.

Polar bears live in the Arctic region, near the North __________.

Lions are at the top of the __________ because they eat other animals.

Organic __________ come from things like animal waste and compost.

It’s important to __________ the beauty of nature for future generations.

A nature __________ is a place where people protect plants and animals from harm.

__________ are deep, narrow valleys with steep sides, often carved by rivers.

The melting of ice caps is a(n) __________ to animals living in cold climates.

Wetlands help prevent __________ by keeping the soil in place.

When leaves fall, they __________ in the soil and become nutrients.

It’s bad to __________ plastic because it harms the environment.

Maintaining a healthy grassland requires careful management of grazing animals.

Desert organisms, like camels, have thick skin to protect them from the sun.

The government recruits people to protect endangered animals in forests.

Toxic substances from factories can also make rivers and lakes unsafe for drinking.

Earth's natural systems help regulate the balance of life on the planet.

Sustainable farming is vital for growing food without damaging the Earth.