Why would historians prefer primary sources over secondary sources?

Where did washington’s army spend a harsh and difficult winter in 1777–1778?

What indian ruler was converted to buddhism? a. ashokab. chandraguptac. brahmand. siddhartha gautama

How did its location near the sea most contribute to the growth of ancient greece? a.by supplying water for irrigating crops b.by providing easy access to trade routes c.by creating a natural barrier from enemies d.by generating power for watermills