A statement of scientific fact. A question which arises from observations. The evidence suggested that the environment caused the variations in life histories of guppy populations. The evidence suggested that differential predation was the most likely cause of the variations in life histories of guppy populations. The evidence suggested that differential food availability caused the variations in life histories of guppy populations.
Enzymes are molecules composed of atoms.
Current cell theory emphasizes that cells are the lowest level of organization that display all of the properties of life. This quote emphasizes the age of the earth and that the the environment on earth changes. If the hypothesis is tentatively accepted, it can lead to further tests of the hypothesis.