Which of the following is an ecosystem service of biodiversity? SELECT ALL THAT APPLY a Nitrogen fixation. b Maintaining the atmosphere by plants and algae. c Preventing soil erosion. d Purifying water in rivers and lakes.

## Step 1<br />Ecosystem services are the benefits that humans obtain from ecosystems. These services include provisioning services like food and water; regulating services such as flood and disease control; cultural services such as spiritual, recreational, and cultural benefits; and supporting services such as nutrient cycling that maintain the conditions for life on Earth.<br /><br />## Step 2<br />Nitrogen fixation is a process where nitrogen in the atmosphere is converted into ammonia or related nitrogenous compounds in soil. This process is essential for plant growth and is a supporting service provided by certain bacteria and cyanobacteria.<br /><br />## Step 3<br />Maintaining the atmosphere by plants and algae refers to the process of photosynthesis, where plants and algae absorb carbon dioxide and release oxygen. This is a regulating service that helps in maintaining the balance of gases in the atmosphere.<br /><br />## Step 4<br />Preventing soil erosion is a regulating service provided by vegetation. Plant roots hold soil in place, preventing erosion by wind and water.<br /><br />## Step 5<br />Purifying water in rivers and lakes is a service provided by wetlands and other aquatic ecosystems. They filter out pollutants, improving water quality.