(2.79) Understand that plants respond to stimuli

·         Stimuli are changes in the environment (temperature, light changes)

·         Plants receptors detect the stimuli and turn it into a response

·         The responses take the form of growth

·         Growth in response to stimuli is called tropism

o    Tropism that involve light are called phototropism

o    Tropism that involve gravity are called geotropism

·         The connection between the receptor and the response usually takes the form of plant hormones sometimes know as plant growth regulators