7. When two solids intersect , they form a boundary where the solids overlap.The lines can either be straight or curved. State the name of the straight or curved lines. (2 marks)

## Step 1<br />The problem is asking for the name of the lines that are formed when two solids intersect. These lines are the boundaries where the solids overlap.<br /><br />## Step 2<br />The lines can either be straight or curved. The term for these lines is "edges". <br /><br />## Step 3<br />Edges are the lines where two faces of a solid meet. They can be straight, as in the case of a cube, or curved, as in the case of a sphere.