The Canadian Shield refers to the exposed portion of the continental crust underlying North America. The crust, also known as the North American Craton, consists of rock from the Archean and Proterozoic eons and extends from Mexico to Greenland. The Canadian portion runs from central Ontario<span> north to the </span>Arctic Archipelago, and fromLabrador<span> west to the </span>Northwest Territories<span>. The Shield includes some of the oldest rocks on Earth (possibly more than 4 billion years old). While at times a barrier to settlement, the Shield has also yielded great resources, including </span>minerals<span>, </span>coniferous forests<span> and the capacity for</span>hydroelectric<span> developments.</span>
Explanation:
Given the importance of oxygen for animals, researchers suspected that a sudden increase in the gas to near-modern levels in the ocean could have spurred the Cambrian explosion. ... This supported the idea of oxygen as a key trigger for the evolutionary explosion.
Answer:
Energy is transferred from the sun to Earth via electromagnetic waves, or radiation. Most of the energy that passes through the upper atmosphere and reaches Earth's surface is in two forms, visible and infrared light. The majority of this light is in the visible spectrum.
Independent Variable is manipulated.
