Question

6/10
how are zircons used in absolute dating?
uranium breaks down into lead,
so determining how much lead
is in a zircon will give an age
looking at the amount of
uranium and lead. more uranium
equals older rocks.
zircons develop rings, like trees,
so you can count them to
determine a rocks age

Explanation:

Zircons incorporate uranium into their structure as they form, and uranium radioactively decays into lead at a known constant rate. By measuring the ratio of uranium to lead in a zircon, scientists can calculate the time elapsed since the zircon formed, which is the absolute age of the zircon (and the rock it formed in). The other options are incorrect: zircons do not form growth rings like trees, and more uranium does not equal an older rock (it is the ratio of uranium to lead that matters, not just the amount of uranium).

Answer:

Uranium breaks down into lead, so determining how much lead is in a zircon will give an age