At EVERY point on Earth . . . North of the equator, South of the equator, at the poles, or exactly ON the equator . . . the lengths of days and nights change with the seasons. (probably supposed to be <em>choice-3</em>)
Human activity is the main cause of climate change. People burn fossil fuels and convert land from forests to agriculture. ... Burning fossil fuels produces carbon dioxide, a greenhouse gas. It is called a greenhouse gas because it produces a “greenhouse effect
