chandler fuller 2/13/14 p.5
the turning of all or part of an organism in a particular direction in response to an external stimulus
the growth of the parts of plants with respect to the force of gravity. The upward growth of plant shoots is an instance of negative geotropism.
the growth or turning of plant roots toward or away from moisture.
Phototropism is the growth of organisms in response to light. It is most often observed in plants, but can also occur in other organisms such as fungi.
The turning or bending response of an organism upon direct contact with a solid surface or object.