Which of the following statements is/are CORRECT?
1. Naturally occurring isotopes account for only a small fraction of known radioactive isotopes.
2. A few radioactive isotopes with long half-lives, such as U-235 and U-238, are found in nature.
3. Trace quantities of some short-lived radioactive isotopes, such as C-14, are found in nature because they are formed continuously by nuclear reactions.
a. 1 only
b. 2 only
c. 3 only
d. 1 and 2
e. 1, 2, and 3
answer D
2 answers
I think 3 is right so it can't be D.
A rock has 76% of its radioactive isotopes. Is it young or old explain