Answer:
Scientist come to know about the land feel by various measures such as quantity of methane gas, quantity of radioactive materials, etc. They collect data from a particular area and checks it whether it is under critical range or not.
Step-by-step explanation:
Land-filling is a process by which all the waste which is solid is buried under the ground. It is also a type of land pollution. It degrades the land quality. The land is no more fertile to grow crops. some of the waste are also radioactive which harmful effect the animals and plant living in that area. It also tends to have the humans living nearby that area. this area is also capable of creating methane gas which is very explosive in nature.
Scientist plays an important role for finding out the critical condition of land. They also have instrument which are very helpful for finding out the critical range of the radioactive materials.