In the Bohr model, what holds the electron in orbit? Select one:
a. a gravitational force
b. the energy of the sun
c. the attraction of the positive proton and negative electron
d. the track that is laid out around the nucleus

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.