Hi there! Do you know what the EPA is? The EPA is a government agency that helps protect the environment. They use something called "methods" to help them test things in the environment to see if they are safe or not.
Let's say you wanted to know if the water in a lake was safe to swim in. The EPA would use a method to collect a sample of water from the lake and test it to see if there are any harmful things in it, like bacteria or chemicals.
Now, there are lots of different ways to test things, and each way is called a "method." Some methods use machines to do the testing, while others use chemicals or even living things like plants or animals.
The EPA has a whole bunch of different methods that they use for different things. For example, they have a method to test for lead in drinking water, and another method to test for air pollution from factories. Each method is really important to help make sure that our environment stays safe and healthy.