Two important of mahajanpadas​

The Magadha was one of the most prominent and prosperous of mahajanapadas. The capital city Pataliputra (Patna, Bihar) was situated on the confluence of major rivers like the Ganga, Son, Punpun and Gandak. ... All these factors helped Magadha to emerge as the most prosperous state of that period.

i think it’s a. this is because if they measured the mass of something with a mass of 150g, then their final answer would have to be approximately 150g. though all of their answers are almost 150, rosa and tran have the closest answers (or the exact answer) to the accurate one.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it