What do these two changes have in common? mixing lettuce and salad dressing building a tower out of magnetic blocks Select all that apply. Both are caused by cooling. Both conserve mass. Both are changes of state. Both are only physical changes.

## Step 1<br />The problem presents two different scenarios: mixing lettuce and salad dressing, and building a tower out of magnetic blocks. We are asked to identify the commonalities between these two changes.<br /><br />## Step 2<br />The first option is "Both are caused by cooling." This is not a commonality between the two scenarios. Cooling is not a factor in either mixing lettuce with salad dressing or building a tower with magnetic blocks.<br /><br />## Step 3<br />The second option is "Both conserve mass." This is a commonality between the two scenarios. In both cases, the total mass of the substances involved does not change. When you mix lettuce with salad dressing, the mass of the lettuce and the dressing combined is the same as the sum of their individual masses. Similarly, when you build a tower with magnetic blocks, the total mass of the blocks remains the same, even though their arrangement changes.<br /><br />## Step 4<br />The third option is "Both are changes of state." This is not a commonality between the two scenarios. Neither mixing lettuce with salad dressing nor building a tower with magnetic blocks involves a change of state. The substances involved remain in their original state.<br /><br />## Step 5<br />The fourth option is "Both are only physical changes." This is a commonality between the two scenarios. In both cases, the substances involved do not undergo any chemical change. The lettuce and the dressing retain their original properties when mixed, and the magnetic blocks retain their magnetic properties when arranged to form a tower.