Question

what do these two changes have in common? boiling sugar to make caramel snails growing shells select all that apply. both are only physical changes. both are chemical changes. both conserve mass. both are caused by cooling.

Explanation:

1. Boiling sugar to make caramel is a chemical change as the sugar undergoes a chemical reaction to form new substances with different properties. Snails growing shells involves complex biochemical processes, also a chemical change.
2. According to the law of conservation of mass, in both chemical - change processes, mass is conserved.
3. These are not just physical changes as new substances are formed. And they are not caused by cooling.

Answer:

Both are chemical changes.
Both conserve mass.