Mayans knew the best time to harvest crops and could predict eclipses due to their study in which subject?
a) astrology
b) astronomy
c) biology
d) mathematics

b. Astronomy.

Explanation:

Mayan astronomy, which indeed, is based on observation and a highly refined mathematical system, is the specific field in which the Pre-Columbian Mayan civilization excelled, even to a higher degree than their European contemporaries. Their measurements of astronomical phenomena allowed them, amongst other things, to predict eclipses and ascertain the best time to harvest. Some of the calculations of the Mayan civilization still marvel contemporary scientists.

general allotment act (dawes act) february 8, 1887

amendment to the dawes act, february 28, 1891

commission to the five civilized tribes (dawes commission), march 3, 1893