Question

why are expansion and contraction considered to be changes that are the reverse of each other?​

Answer 1

Answer:

The process of change of state or the physical changes is reversible. There is no change in total mss. Flowing happens in liquid and gas but not in solid. The expansion is an increase in size and occurs in objects when they get warmer; they tend to contract or decrease in size when they get more cooling.

Answer 2

Expansion:

Expansion is nothing but the increase in size or expanding of organ.

For example when we breathe air in the lungs face expansion in result of our action.

Contraction:

Contraction is nothing but the decrese of size or the organ regaining its original state from expansion.

For example if we breathe air out the lungs face contraction in result to our action.

Hence, they are said to be reverse of each other.

Hope this helps you.