Why do winter constellations go away in summer and summer constellations go away in the winter?

Question

Why do winter constellations go away in summer and summer constellations go away in the winter?

Answer 1

they are on opposite sides of the sun

Answer 2

They don't go away, but as the Earth revolves around the Sun, the Sun's apparent position in relation to the stars changes.  As a result, the winter constellations you see during winter nights are not visible in Summer because the movement of the Earth in it's orbit puts the Sun in the same part of the sky as the winter constellations, thus preventing us from seeing them.  Likewise for the Summer constellations.

Answer 3

Why do you think they are called summer constellations?!