The gravitational force is being felt as the Earth pulls the train downwards using the two forces. The coils that provide the forces releases an electrical current which makes an electromagnetic field. It repels the materials with an equal force that goes up as well.
If the predator that feeds off the dart frogs goes extinct or migrates to a different area then the dart fronts will have a much larger population. This means that the resources the dart frogs rely on will start to deminish and their prey will have smaller numbers
Gravitropism or geotropism which is a growth response to gravity
a growth response to light is called phototropism
