I believe it's answer #3. Logically, at least.
You can test #1 through trial and error.
You can experiment #2 also through trial and error.
You cannot test #3 through trial and error, because that would be catastrophic.
You can test #4 through a survey and individual study and data collection.
Carbon (24.00)(2)+hydrogen(1.01)(6)
The type of environment that just fits the characteristics of a certain species is called a habitat.
