Will mark brainliest ! the table below shows the half-life of an element: half-life data element half-life uranium-235 700 million years scientists have found that the uranium-235 content of an unknown prehistoric sample was reduced to one-half. what best describes the identity of the sample? a. a rock that formed 700 million years ago b. a rock that formed 1,400 million years ago c. an organism that died 700 million years ago d. an organism that died 1,400 million years ago