7. a place or object (like a stop sign or mailbox) used for comparison to determine if another object is in motion
is called a
a comparison point
c. point of view
b. frame of reference
d. motion detector

Will you chech and finish these for me, because i am stumped with them.

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !

Sodium chloride, nacl, is formed when a sodium atom transfers its electron to a chlorine atom. the difference in charge between the two atoms creates a(n) attraction that bonds them together.