Aneutral atom of potassium (k) has an average mass of 39 amu and 19 electrons. how many neutrons does it have?

Aknife blade is a(n) a. lever b. screw c. wedge d. inclined plane

Because air contracts as it cools, the air pressure inside a freezer is typically lower than on the outside. why do ice cubes inside a freezer tend to shrink over time? a. the ice dissolves oxygen from the air, forming a denser crystalline matrix.b. the ice reacts chemically with carbon dioxide in the air, forming gaseous carbon compounds.c. the ice melts, and then the liquid freezes as ice crystals on the bottom of the freezer.d. the ice sublimes, and then the water vapor deposits as ice crystals on the sides of the freezer.

The heliocentric and the geocentric models of the solar system included these central principles