Answer:
Agriculture allowed people to stay in one place, and increased food production caused the population density to expand far beyond levels that could be sustained by hunting and gathering alone. This growth in population density provided a critical mass of people to sustain and spread contagious infectious diseases.
The main reason why the tectonic plates move is the conversational currents. There is magma between the upper mantle and the asthenosphere that heats up at the upper mantle. The weight is so small that the magma rises with the help of these conversational currents. When the magma has ascended towards the asthenosphere, it has nowhere to go so the magma lies along the asthenosphere. There the magma cools down again because the asthenosphere is colder than the upper mantle, which makes the magma heavier and goes back down to the upper mantle, where the magma heats up again and everything starts all over again and so it goes on over and over again. Scientists have concluded that the earth's gravity causes two other processes that also cause the tectonic plates to move.
Ridge push - in the spreading zones, the sides of the tiles are raised and slide to the side as in a slide.
Slab pull - when a plate is pulled down by gravity in a subduction zone like an anchor.
Answer:
Sierra Madre Occidental
Explanation:
this mountain range takes up nearly 140,000 square miles of Mexico.
Answer: A member of Congress might attach a rider to a bill in order to get a controversial provision in the bill get passed with the passage of the bill.
Explanation: A rider is nothing but another provision added to a bill that may otherwise be considered as a controversial bill in whole without the inclusion of the rider. The rider acts as a puller to the other controversial provisions of the bill that the member of Congress intends to get passed.
Answer with Explanation:
A canyon is a natural area where both living and non-living organisms are found. Residing near it brings several benefits. <u>One of these is having the opportunity to exercise.</u> A person may access the canyon for his daily jog or walk. He may also do a little bit of hiking.<u> Another benefit is having good quality of water (free from pollutants).</u> The vegetation in the canyon prevents the urban runoff (usually from storms) from polluting the bodies of water.<u> Lastly, it gives the person a chance to see wildlife.</u> Many of the canyons are being preserved; thus, it's an opportunity to see many endangered habitats in it.
