Question

the radioisotope, iodine-131, is often used to...
select one:
a. determine a fossil’s age.
b. treat cancer.
c. treat thyroid problems.
d. fuel a nuclear reactor.
radiocarbon dating can be used to determine the age of a fossil because the amount of carbon-14 found in the fossil...
select one:
a. increases steadily over time.
b. decreases steadily over time.
c. is unaffected by time.
d. remains the same for the first 10 years, and then rapidly decreases.

Explanation:

1. For iodine-131: The thyroid gland absorbs iodine preferentially, so this radioisotope is targeted to treat thyroid disorders by destroying overactive or abnormal thyroid tissue.
2. For radiocarbon dating: Carbon-14 is a radioactive isotope that decays at a constant known rate. Once an organism dies, it stops taking in new carbon-14, so the amount of carbon-14 in its remains decreases steadily over time, allowing age calculation.

Answer:

1. c. treat thyroid problems.
2. b. decreases steadily over time.