Step 1: Understand soil remediation techniques.
Soil remediation refers to the process of removing contaminants or pollutants from the soil to restore its health.
Step 2: Identify the role of fungi in remediation.
Mycoremediation uses fungi to absorb or break down harmful substances, such as heavy metals, from contaminated soils. Fungi have a natural ability to degrade or absorb these pollutants.
Step 3: Confirm the correct answer.
The process of using fungi to clean up toxic heavy metals from soils is called mycoremediation. Therefore, the correct answer is (4).