Number 1 pls

This large tectonic plate is bounded on three sides by whats know as the ring of fire. what is the name of this tectonic plate? a) pacific plate b) eurasian plate c) north american plate d) indo- australian plate plz it's science but there's no option for science so i picked chemistry

Calculate the number of molecules present in 0.750 mol of mgo.

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.