How do we know about lewis and clark’s discoveries?

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.

yes based on alexanders actions he deserved the title of "the great". his empire covered about 3,000 miles and he was able to establish the empire over a 13 year period of time. he was able to conquer many different places. he also defeated the persians. he conquered egypt and developed a city and named it after himself.