Our Amazing Atmosphere

Front

When did oxygen first become a major part of our atmosphere?

Back

Around 2 billion years, after photosynthetic life had evolved.

Front

Our daily weather occurs in this layer of the atmosphere.

Back

troposphere

Front

Air becomes saturated with water vapor when it is cooled to this temperature.

Back

the dewpoint

Front

The hot young Earth was volcanically active. The eruptions released large amounts of ______, which was the main gas in our atmosphere at that time.

Back

water vapor

Front

Gases in our atmosphere help regulate our _____, making it possible for liquid water to exist at the surface.

Back

temperature

Front

This gas in the stratosphere protects us from harmful ultraviolet solar radiation.

Back

ozone

Front

Water vapor can enter our atmosphere by evaporation from lakes, rivers, and the ocean. It can also enter the atmosphere from plants through a process known as ___.

Back

transpiration

Front

Temperature increases as you go higher in the stratosphere because ___ gas is absorbing ultraviolet radiation. Options: nitrogen, oxygen, ozone, carbon dioxide

Back

ozone

Front

When dew forms on the grass in the morning, what is the relative humidity of the air around the grass?

Back

100%

Front

When air pressure drops, temperature ___.

Back

drops