Which early civilization had a well organized unified empire with an elaborate system of roads covering more than 10,000 miles?

Incas is the correct answer.

Explanation:

Inca Empire existed in modern day Peru and was largest empire in pre-columbian America. It was established by Manco Capac in 1438, it  extended from Quito to Santiago and covered areas of at least 2 million kilometres. Quechua was their official language. One major characteristic of the Incas was that they had constructed more than 30,000 kilometres of roads. Inca civilisation ended in 1532 with the arrival of Conquistadors. They had strong belief in life after death.

try c, it's always the answer. pats suck.

a hypothesis is an expected answer to a question, usually based on some theory or prior research. hypothesis testing is a method of determining the viability of a hypothesis. let’s use the us presidential election as an example. there are many hypotheses (questions) about how people feel or whom they will vote for. the only way to know the 100% “truth” about the answers to these questions is to ask every single possible voter – something that is impossible, expensive, time consuming etc. instead, we take samples and use statistics to make “best guesses” about the answer to a particular hypothesis. we never know for sure if our conclusion is right at the time we accept/reject it, but these techniques, when used appropriately can get us close to the truth most of the time (which is a lot better than guessing, flipping coins or throwing darts to get answers).

the tricky part about hypothesis testing is that we have to think somewhat backwards about it – we have to test what is known as the “null hypothesis”. as an example, the hypothesis might be “obama is more popular than romney” while the null hypothesis is “there is no difference in popularity between obama and romney”. we focus on the null hypothesis because it tells us exactly what the expected value of our tests should be (obama popularity = romney popularity) and we can collect data and see if it comes out that way (see next section on “significance”). if it does, then we “accept the null hypothesis” and reject our original hypothesis. if the null hypothesis is disproven, we look at the data to see if our original hypothesis holds (obama> romney).