Can someone help me please? :/ Regular eclipses of the Sun and the Moon are best explained by which of the following?

1: The movement of Earth and the Moon around the Sun

2: The relative masses of the Sun, Earth, and the Moon

3: The different compositions of the Sun and the Moon

4: The rotation of Earth and the Moon on their axes

Aray of light traveling parallel to the principal axis of a concave mirror will be reflected through the mirror's

You are traveling in a car going at a constant speed of 100km/h down a long, straight highway. you pass another car going in the same direction which is traveling at a constant speed of 80km/h. as measured from your car's reference frame this other car is traveling at −20km/h. what is the acceleration of your car as measured from the other car's reference frame? what is the acceleration of the other car as measured from your car's reference frame?

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