This is known as the visible spectrum of electromagnetic radiation, or visible light. This is the frequency of light that we see, and which illuminates our world as it reflects off of objects. Compared to the full spectrum of electromagnetic radiation, the visible light portion is actually quite small.
Answer:
la agricultura se revolucion en el año de la mesopotamia
1/3 of the population growth
Glaciated valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring. When the ice recedes or thaws, the valley remains, often littered with small boulders that were transported within the ice, called glacial till or glacial erratic.
Fast growing cities rarely had sewage systems which increased disease. Also many factories let out pollutants in the air. They also had few safety regulations and employed children, usually orphans, leading to many accidental deaths due to machinery and fire.
