Why an embankment dam's lower part is kept wider than the upper part?

We have a colorless transparent liquid. it looks like water. we seperated it into a solid and a liquid by evaporration and condention was this a chemichal or a physical seperation a. chemical seperation b. physical seperation

While you are driving in the lane next to the curb on a multi-lane road the car on your left suddenly moves toward you lane. they are about toy crash into your front fender. you

Holes drilled several kilometers into earth’s crust provide direct evidence about earth’s interior in the form of