select all the correct answers. sally works as a geologist in the southwestern united states. he plans to…

select all the correct answers. sally works as a geologist in the southwestern united states. he plans to choose an unstable isotope to find the absolute age of a rock sample. which two aspects must he consider before making his choice? there should be a sufficient amount of the selected isotope in the rock. the isotope should be one that decays at a very fast rate. the isotope must not be found in any neighboring rocks. the half - life of the isotope must be long enough to capture the age of the rock. there should be more than one unstable isotope in the rock.
Answer
Brief Explanations:
To find the absolute age of a rock sample using an unstable isotope, there needs to be enough of the isotope in the rock for detection and analysis. Also, the half - life of the isotope should be long enough to cover the time span of the rock's age. A fast - decaying isotope may not be present in sufficient amounts for old rocks, and the presence or absence in neighboring rocks is not a key factor for determining the rock's age. Having more than one unstable isotope is not a necessary condition for age - determination with one isotope.
Answer:
There should be a sufficient amount of the selected isotope in the rock. The half - life of the isotope must be long enough to capture the age of the rock.