Nitrogen is cycled out of the atmosphere due to

Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to the rest of the body?

In the 1500s, an astronomer developed a new model of the universe. this model had the sun at the center of the universe, not earth. who was this astronomer?

How were royal colonies different from corporate colonies? what was the king's privy council? what role did it play in the house of burgesses? what led to the creation of the rhode island colony? how was the colony governed?