4.564000 x 10^-4 express how many significant figures

Why is soap used to remove grease? a. its nonpolar end dissolves the grease. b. it makes the water bond with the grease. c. it chemically bonds with the grease. d. its polar end dissolves the grease.correct answer for apex - a, its nonpolar end dissolves the grease.

The excretory system,need answers for all: )

Anthracite is so hard and pure it is also referred to as a renewable resource metamorphic rock hot bituminous coal dirty fuel