Question

what do these two changes have in common?
filtering air to remove dust and pollen
building a tower out of magnetic blocks
select all that apply.
both are only physical changes.
both are caused by heating.
both are changes of state.
both are chemical changes.

Explanation:

Filtering air separates dust/pollen from air without changing their chemical identities; building a tower rearranges magnetic blocks but doesn’t alter their composition. Both are physical changes (no new substances form). Heating isn’t involved, neither is a state change (solid/air remain in original states), and no chemical reactions occur.

Answer:

Both are only physical changes.