The first thing that the farmer should do is formulate a hypothesis in which he will make intelligent guesses on what is happening or develop a theory of which would explain what is happening. It is the first step in scientific investigation in order to formulate questions of why weeds that are sprayed does not die. After this, it is only then the farmer should experiment and after that, he should finalize his findings as it is its conclusion to the problem.
The four main functions of glial cells are: to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy and remove the carcasses of dead neurons.