The sun appears to cross the plane of Earth's equator
when it reaches either one of the "equinox" points in the sky.
At those times, the lengths of day and night are nominally equal
everywhere (except at the poles), and the occasions are marked
as the beginning of Spring and Autumn.
Answer:
not sure, but most likely answer b: variation's in the shape earth's orbit
Explanation:
Mountain effect refers to the windward side of the mountain receiving precipitation. It is also the effect of rough terrain on radio-wave propagation. Thus, it caused reflections that produce errors in radio direction-finder indications.
