UNIT2 REVISION- LIVING THINGS IN THE NEVIRONMENT

A gas that constitutes 21%

in the atmosphere.

• oxygen

• nitrogen

• carbon dioxide

• sulfur

To become ________ means the number of one kind decreases over the year.

To be gone completely and never exists anymore means ____________.

• endangered

• extinct

• migrate

• hibernate

People clear forest

for _____________.

When trees are cut down in the rainforest, it can take _________ for new trees to become fully grown.

• 2 years

• 10 years

• 50 years

• 100 years

Forests trees remove carbon dioxide to help reduce global warming. Also, they give out

_________which humans and animals need to survive.

The act of replanting trees on an area of land that has become empty or spoiled

• deforestation

• reforestation

• Recycling

• Afforestation

a gas that causes the greenhouse effect, especially carbon dioxide

• warehouse gas

• whitehouse gas

• greenhouse gas

• blackhouse gas

Sulfuric acid is formed when sulfur oxide dissolves in liquid.

• TRUE

• FALSE

Many animals eat other animals. These animals are predators and the animals they eat are their __________.