Earth being a certain distance from the sun means a certain amount of energy is a vailable, and life grew to meet the energy. (religion.blogs.cnn.com)
Otherwise, she wouldn't have been a person at all but a certain amount of energy or matter that would have been part of the total world but in no sense identifiable as this woman. (religion-online.org)
This low efficiency results from the fact that only photons with a certain amount of energy — that is to say, only part of the solar spectrum — can sufficiently energize the electrons to form the current; other photons are essentially wasted. (scientificamerican.com)