Which of the Following Statements Is/are CORRECT

question 42

Multiple Choice

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

---

Definitions:

Method

A systematic way of doing something, often involving a detailed series of steps or procedures.

Pathogens

Microorganisms that cause disease in humans and other living hosts.

Immunity

The body's ability to resist or eliminate potentially harmful foreign materials or abnormal cells, including pathogens and cancer cells.

Disease

A disorder of structure or function in a human, animal, or plant, especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury.