Grade 9 Composition & Structure

Envelope of air that surrounds us is __________and it is held to the Earth by _____________.

• Atmosphere , Equity

• Atmosphere, Density

• Atmosphere, Gravity

The density of air _______ with _______in height.

• increases, decreases,

• decreases, increase

• decreases,decreases

Total mass of air is found on

• Earth's interior

• Earth's surface

• Earth's bottom

Ultraviolet and infrared rays of the sun help in __________ the warmth of the Earth.

• increasing

• retaining

• destroying

____________help in circulation of water vapor.

• x rays

• sun's rays

• UV rays

___________dilutes the oxygen and slows down the process of oxidation.

• Helium

• Oxygen

• Nitrogen

Least % of gases are _______________,______________.

• Water vapor

• oxygen

• Nitrogen

_______________,_____________,_______________are nuclii for water vapor to form raindrops.

• water vapor, meteorites, smoke

• water vapor, meteorites, stone

• water vapor, ozone, smoke

_____________always remains in contact with land and water.

• Air pressure

• wind pressure

• pressure

Large mass of air is moved up and down the Atmosphere . So it is a ________________ entity.

• mobile

• dynamic

• static