Which best fills in the blank beside number 1 in the outline?

I’n a rough draft, where should the main idea first appear in the paper

Diego rivera was a famous artist from mexico. most of his paintings were murals. murals are paintings that are made directly on a wall. rivera thought that all people should be able to see beautiful art, not just people who could afford to go to museums. this is why he painted most of his murals on the walls of public buildings

Which website most likely provides reliable information about climate change?