About what fraction of the Earth’s atmosphere is NOT made of nitrogen? Give your answer as a reduced fraction.

Hich of the following best summarizes the text’s depiction of the ancient indus valley cities (namely harappa and mohenjo-daro)? a. the cities were very plain and simple; the people did not focus on art and architecture, devoting their time instead to agriculture and the bare essentials. b. the cities were adorned, or decorated, with almost overwhelming displays of wealth and artistic architecture. c. the cities were extremely clean, relying on an advanced water and sewer system, though this was mainly constructed for the innermost areas of the cities. d. the cities were clean and peaceful, and they were designed in an extremely organized fashion, using an advanced water and sewer system to keep them this way

What causes the cyclical changes in the appearance of the moon?

People make choices about how to use resources.