When using science to investigate physical phenomena, which characteristic of the event must exist?

predictable

observable

provable

readable

observable

Explanation:

In order for an experiment to succesfully take place, the experiment must be controlated, observable, and repeatable, this means that under certain circumstances that you are able to control, you can observe an event and investigate it. It has to be observable in order to gain and gather information about the event and with this be able to come up with a conclusion of factor that make it possible and the consequences that the given event has.

c

the articles of confederation placed most of the power on the feds

answer; i believe that the correct answer is (c) arctic tundra;