Question

what do these two changes have in common? sanding a piece of wood dew appearing on grass in the morning select all that apply. both are caused by cooling. both are chemical changes. both are only physical changes. both conserve mass.

Explanation:

Sanding wood is a physical change as it only alters the shape and surface of the wood without changing its chemical composition. Dew forming on grass is also a physical change, a result of water vapor condensing (a physical state - change) due to cooling. According to the law of conservation of mass, in both physical changes, mass is conserved as no new substances are formed.

Answer:

Both are only physical changes.
Both conserve mass.