Attending an in state college
(2) U-238 is the radioisotope used in dating geological formations. Uranium-238 has a half-life of 4.46 billion years, which makes it suitable to date such old formations.
The other options do not have such long durabilities and half-lives.
The law of conservation of energy states that no energy is created nor destroyed. When using a backup generator, the generator uses energy from another resource.
