____________ is the percentage of nitrogen in air.

Gas exchange takes place in plants using __________

The constituent of air that supports combustion is _________________

Nitrogen is used in the food packaging industry because it ________________

_______ and _________ are the two gases, which when taken together, make up about 99 percentage of air.
I. Nitrogen
II. Carbon-di-oxide
III. Noble gases
IV. Oxygen

__________ is the active component of air.

The gas given out during photosynthesis is _________.

__________ gas is given to the patients having breathing problems.

__________ can be seen moving in a beam of sunlight in a dark room.

What will happen if we remove plants from the aquarium?

What is atmosphere? Name the five layers of atmosphere

How do the roots of land plants get oxygen for breathing?

What should be done if the clothes of a person catch fire accidentally? Why?

What will happen if you breathe through mouth?

Biscuits kept open on a plate during monsoon days lose its’ crispness. Why?

Why do traffic assistants wear a mask on duty?

How do plants and animals maintain the balance of oxygen and carbon-dioxide in air?

Why is atmosphere essential for life on earth?

Can you guess why fire extinguishers throw a stream of carbon-di-oxide while putting - off fire?