In the picture above, object A is at rest (not moving relative to Earth) and the other 3 spectra come from objects that are moving towards the observer. Which object is (or which objects are) being blueshifted relative to Earth

Need in all of themmm only answer if you know plsssss

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 !

What kind of simple machine is a catapult?