Why were there few accounts written by slaves about their lives during the antebellum era?

The arizona department of transportation wishes to survey state residents to determine what proportion of the population would like to increase statewide highway speed to 75 from 65 mph. at least how many residents do they need to survey if they want to be at least 99% confident that the sample proportion is within 0.09 of the true proportion?

How was the appointment of two consuls during the roman republic an example of a democratic principle? one consul represented patricians and one represented plebeians, so that all citizens had representation each consul had control over the same number of military legions, which prevented either one from a forceful takeover. consuls had to agree on all decisions, which prevented any one person from gaining too much power. consuls had to make decisions based on majority rule in the senate. quickly

Refers to the biological heritage people use to identify themselves.