Answer:
The time span between 1680 and 1766 (lines 1 and 2) is 86 years: 1766 − 1680 = 86 years. During this time, the falls receded an average of 5.8 feet per year: 500 feet ÷ 86 years ≈ 5.8 feet per year.
The time span between 1856 and 1876 (lines 3 and 4) is 20 years: 1876 − 1856 = 20 years. During this time, the falls receded an average of 25 feet per year: 500 feet ÷ 20 years = 25 feet per year.
Explanation:
plato answer ^
The sun and the planets formed together 4,6 billion years ago from clouds of gas and dust called the solar nebula
The sky is blue because blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
Oceanic Trench or Deep Sea Channel, it is a narrow, long and having a sharp inclination depression in the lowermost deep-sea in which happen the extreme oceanic depths. They normally form in places where once the structure of the earth's crust plate <span>is forced below the edge of</span> another. While Abbysal plain is a beneath the surface of the water plain on the deep ocean floor, typically found at depths approximately 3,000 meters and 6,000 meters. It is in a horizontal position largely between in a mid-ocean ridge and a foot of a continental rise. Almost 50% of the Earth’s surface was sheltered by Abbysal Plains. They are the smoothest and flattest and not so discovered areas on Earth.