He measures the amount of radioactive uranium in the sample and compares it to the amount of radioactive lead. He then compares these amounts to the rate at which these two radioactive materials decay.

What is Rex most likely trying to figure out about the rock formation?

wheres the answers ?

answer; ///i believe the correct answer is (aids) acquired immune deficiency syndrome;

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]