Complete the summary below.
Choose NO MORE THAN TWO WORDS from the passage for each answer.
Write your answers in boxes 20-24 on your answer sheet.
(20) is a series of actions leading to tensional oscillation. Various components move back and forth from the force of the (21) Eventually the structure absorbs more (22) than it is able to disperse and the (23) increase in intensity until the structure collapses under the (24) .
(20)