Here i hope this helps, let me know if you need clarification on anything :)
The answer is false, pumice is a rock formed from the smoggy powder that shoots out of a volcano called pumicite.
You got the formulas on the sheet on the top :) So just use those, exchanging v (as in velocity, expressed in m/s) and the d (in meters) and t (in seconds). Hope you will manage it.
Yes. Organisms do work together to make another level of organization. They work together to make organ systems.