Multiple choice

Which of these fits gap 22?

Directions: Complete this passage by selecting the most suitable option for the corresponding gap.
Radium is a radioactive element. Let us see what “radioactive” _____ (21) ____. 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 ____ (22) _____ is called “radio activity”. Each radioactive element disintegrates by giving off rays at a certain rate. This rate cannot be _____ (23) ____ or slowed down by any known method. Some changes occur rapidly, others slowly, but in all cases the action cannot be _____ (24) ______ by man.

  1. tear off

  2. failure

  3. decay

  4. build up
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Here we are looking for a similar meaning word as decay, which out of the four given options is 'decay'.

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