The Sun provides the heat needed to change the temperature of substances, leading to physical changes. These changes involve a change in state but do not change the chemical composition of the substance.
The Sun would affect physical changes seen in the illustration by providing the heat needed to change the temperature. Heat from the Sun can cause substances, such as ice, to change their state -- for example, melting the ice into liquid water. This is because when heat flows into a substance at its melting point or boiling point, the energy allows the particles to move more freely, changing the physical state from solid to liquid or from liquid to gas.
A physical change does not alter the chemical composition of a substance; it just affects its physical properties. For example, when liquid water is heated and changes to water vapor, it's still composed of two hydrogen atoms covalently bonded to one oxygen atom, so its molecular structure remains unchanged. The Sun does not cause new substances to form from the original ones, prevent the formation of a precipitate in the beaker, nor is its light necessary for these phase changes to occur.
Therefore, the correct answer to how the Sun would affect changes seen in the illustration is 'a) It provides the heat needed to change the temperature,' leading to physical changes in the state of matter. These changes include melting, evaporation, and possibly condensation if the vapor cools.