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Read the text. Then answer the question.
Earth is surrounded by a layer of gases called the atmosphere. The gases that make up the atmosphere sustain life on Earth. Living organisms take in and release some of these gases. Gases in the atmosphere also help insulate Earth from extreme temperatures and block some harmful forms of sunlight.
Earth's organisms rely on the atmosphere for which of the following? Select all that apply.
The circle graph below shows the concentrations of the gases that make up Earth's atmosphere, except for water vapor.
The concentration is the amount of particles in a given volume and is shown here as a percentage of the total number
of gas particles in the atmosphere. Gases present at concentrations less than 1%, such as carbon dioxide, are called trace gases.
Based on the graph, which of the following are true? Select all that apply.
Read the text. Then answer the question.
Complete the statement.
One hundred years ago, the atmospheric concentration of carbon dioxide was about 300 ppm,
or about 0.03% of the gas particles in the atmosphere. In 2015,
the atmospheric concentration of carbon dioxide was roughly____ ppm.
Read the text. Then answer the question.
Earth's atmosphere has always contained greenhouse gases. Natural sources of greenhouse gases include respiration,
decomposition, and volcanic eruptions.
The concentrations of greenhouse gases in Earth's atmosphere have changed over time.
But in recent years, humans have been adding an especially large amount of greenhouse gases to the atmosphere.
One way humans add greenhouse gases to the atmosphere is by burning fossil fuels, such as coal, oil, and natural gas.
Which of the following activities could release greenhouse gases into Earth's atmosphere? Select all that apply.
Which of the following activities could release greenhouse gases into Earth's atmosphere? Select all that apply.
Read the text. Then answer the question.
Molecules of nitrogen (N2) and oxygen (O2) make up 99% of the gas particles in the atmosphere.
The remaining gases are present at much smaller concentrations.
Measurements made in 2015, for example,
showed that carbon dioxide (CO2) made up
roughly 0.04% of the gas particles in the atmosphere.
The amount of a particular
gas in the atmosphere can be expressed as a concentration with
units of parts per million,
or ppm. Parts per million is a measurement of the number of particles out of every
million particles.
So, an atmospheric concentration of 1 ppm means that there is one particle of that gas out of every
million particles of gases in the atmosphere.
The atmospheric concentrations of some gases are so small that theyare expressed in parts per billion or even parts per trillion.
Complete the statement.
One hundred years ago, the atmospheric concentration of carbon dioxide was about 300 ppm,
or about 0.03% of the gas particles in the atmosphere. In 2015,
the atmospheric concentration of carbon dioxide was roughly____ ppm.