Multiple choice

Directions: Fill in the numbered blank (v) with the best option from those given.

Directions: Fill in the numbered blank with the best option from those given.

Radium is a radioactive element. Let us see what “radioactive” _____ (i) ____. Radioactive elements do not change from year to year. But a few of the heaviest atoms break down and change into other kinds. This breakdown or ____ (ii) _____ is called “radio activity”. Each radioactive element _____ (iii) ____ by giving off rays at a certain rate. This rate cannot be _____ (iv) ____ or slowed down by any known method. Some changes occur rapidly, others slowly, but in all cases the action cannot be _____ (v) ______ by man.

  1. diagnosed

  2. controlled

  3. caused

  4. highlighted
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sentence states radioactive action "cannot be ______ by man." "Controlled" is correct because humans cannot alter, influence, or stop radioactive decay processes. "Diagnosed" refers to identifying conditions, "caused" doesn't fit (humans can cause radiation but not control natural decay), and "highlighted" means emphasized, not controlled.

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