Helen is learning about how the Sun can give heat to the Earth without touching it. Which of these would be a good model to help her understand how heat comes from the Sun?

Fossils of ancestors of the modern horses show a small 4-toed almost dog-like browsing animal named eohippus over time the horses got larger lost toes and changed to a grazing diet what is the best explanation of why this change occurred

Why do mountaineers become breathless as they reach high altitudes

Define adaptation. why do organisms adapt? give an example.