Fill in each blank with the correct word from the lesson.

1. Plants and trees help keep our air clean and full of _______.
2. We _______ air about twenty-two thousand times every single day without even thinking about it!
3. Plants absorb this carbon dioxide and make oxygen through _______!
4. About seventy-eight percent of air is a gas called _______, which plants need to grow.
5. When we breathe, our bodies use oxygen and release a gas called _______.

Choose the best option for each question.

1. Which gas do we breathe in from air?
   a) Nitrogenb) Carbon dioxidec) Oxygend) Hydrogen
2. What percentage of air is oxygen?
   a) 78%b) 21%c) 50%d) 1%
3. What do plants give us?
   a) Carbon dioxideb) Nitrogenc) Oxygend) Steam

Write T for True or F for False in the brackets.

1. Plants and trees help keep our air clean and full of oxygen.
2. Plants and trees help keep our air clean and full of Nitrogen.
3. 21% is one of the key concepts in the lesson on Air We Breathe.
4. 78% is the main topic of this lesson.

1. In your own words, explain what Air We Breathe means.
2. List two things you learned from this lesson on Air We Breathe.