He didn't care much about imposed gender roles. He was open minded and only wanted for Scout to be happy and to be a good person. He didn't mind if she behaved like boys did as long as she grew up to be a good person who helps others and is compassionate. This is opposed to the beliefs of her Aunt which believes that Scout should not behave as she is behaving and that she should wear dresses and learn manners like a lady and be more lady-like, as she describes it. Atticus doesn't care about things like this and cares about Scout's upbringing as a person more.
The Nile River was a major life source for the ancient Egyptians.
Answer: it allows people to publicly voice their opinions. It plays an important role in positively influencing government policies.