CK-12 Foundation
Ck 12: Life Science: Tropisms
[Free Registration/Login may be required to access all resource tools.] Plants may not be able to move, but they are able to change how they grow in response to their environment. Growth toward or away from a stimulus is known as a...
BiologyWise
Biology Wise: The 7 Unmistakable Characteristics of Life
Describes the seven characteristics that define life - cells, homeostasis, heredity, use of energy, reproduction, response to environmental stimuli, and evolution and adaptation.