Which substance is a greenhouse gas that is emitted by human activities is the most widespread,and remains in the air the longest? water vapor methane fluorinated gas carbon dioxide

## Step 1<br />Greenhouse gases are gases in the Earth's atmosphere that trap heat. They include water vapor, methane, nitrous oxide, and fluorinated gases. These gases are released into the atmosphere by human activities such as burning fossil fuels, deforestation, and industrial processes.<br /><br />## Step 2<br />Among these gases, carbon dioxide (CO2) is the most widespread and remains in the air the longest. This is because CO2 is released in large quantities from human activities, and it has a long lifespan in the atmosphere.<br /><br />## Step 3<br />The lifespan of CO2 in the atmosphere is much longer than other greenhouse gases. This is due to the fact that CO2 is not easily broken down by natural processes, and it can remain in the atmosphere for hundreds of years.