Scientists use different kinds of investigations depending on the questions they are trying to answer. Simple instruments provide more information than scientists can obtain using only their senses. Scientists make the results of their investigations public, describing it in a way that allows others to repeat the investigation.
Scientists review and ask questions about the results of other scientists' work.
The details are different for different organisms. Some are harmful to the organism, while others are beneficial. Humans change environments in ways that can be either beneficial or detrimental for themselves and other organisms. Changes in environments can be natural or influenced by humans. Some environmental changes occur slowly, and others occur rapidly.