The answer is b an astronomical unit
B shadows
The position of the sun in the sky casts a shadow on a properly placed sundial. This will give you time of day depending where the shadow falls.
Answer:
Contour farming
Explanation:
I think it would be contour farming mostly because none of the others seem to be done on ridges or slopes.
Assuming this involves another form of shifting tectonic plates, the answer would be earthquakes. Another form of the question is asking for continental drift.
