Some species of animals, including some salamanders and crickets, spend their entire lives deep in caves where no sunlight reaches. Predict the main source of energy for these organisms.

water

Explanation:

the reason I think water is because water is probably the only source of nutrients which breaks down to energy

sodium (na), for example, has one electron in its valence shell. this is an unstable state because that valence shell needs eight electrons to be full. in order to fill its valence shell, find a way to add seven electrons to its valence shell