The half-lives of unstable isotopes vary from milliseconds to billions of years

true or false

True

Explanation:

The half lives of unstable isotopes of elements vary from miliseconds to billions of years, for example Bismuth-209 has the longest half life known by the human and the scientists and it has still billions of years to this day, and there are elements that cannot withstand seconds before decaying into another element, so the statement is True.

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.

i think its 100

i hope this !