Which type of change is necessitated unexpected environmental events or pressures?

Reactive changes are the type of changes that are necessitated unexpected environmental events or pressures. Organiyations or businesses make such reactive changes in their practices after some threat or opportunity has already occurred.

Other types of changes are anticipatory changes, that are the oppsite because they are planned changes.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

b - the respond is innate and varies over time.

good luck!