Cover crop roots hold the soil in place, protecting soil from wind erosion. Cover crops can also protect soil from the impact of heavy rainfall and runoff. Reduced erosion protects and improves water quality by keeping ag chemicals in the ground and out of drainage water.
Plastic is a word that originally meant “pliable and easily shaped.” It only recently became a name for a category of materials called polymers. The word polymer means “of many parts,” and polymers are made of long chains of molecules. Polymers abound in nature. Cellulose, the material that makes up the cell walls of plants, is a very common natural polymer.
Over the last century and a half humans have learned how to make synthetic polymers, sometimes using natural substances like cellulose, but more often using the plentiful carbon atoms provided by petroleum and other fossil fuels. Synthetic polymers are made up of long chains of atoms, arranged in repeating units, often much longer than those found in nature. It is the length of these chains, and the patterns in which they are arrayed, that make polymers strong, lightweight, and flexible. In other words, it’s what makes them so plastic.
These properties make synthetic polymers exceptionally useful, and since we learned how to create and manipulate them, polymers have become an essential part of our lives. Especially over the last 50 years plastics have saturated our world and changed the way that we live.
The First Synthetic Plastic
The first synthetic polymer was invented in 1869 by John Wesley Hyatt, who was inspired by a New York firm’s offer of $10,000 for anyone who could provide a substitute for ivory. The growing popularity of billiards had put a strain on the supply of natural ivory, obtained through the slaughter of wild elephants. By treating cellulose, derived from cotton fiber, with camphor, Hyatt discovered a plastic that could be crafted into a variety of shapes and made to imitate natural substances like tortoiseshell, horn, linen, and ivory.
This discovery was revolutionary. For the first time human manufacturing was not constrained by the limits of nature. Nature only supplied so much wood, metal, stone, bone, tusk, and horn. But now humans could create new materials. This development helped not only people but also the environment. Advertisements praised celluloid as the savior of the elephant and the tortoise. Plastics could protect the natural world from the destructive forces of human need.
The creation of new materials also helped free people from the social and economic constraints imposed by the scarcity of natural resources. Inexpensive celluloid made material wealth more widespread and obtainable.
Answer:
Depends on what kind of change
Explanation:
Change as in "I will change my answer": switch
Change as in "I have so much loose change in my purse": coins
The Spoils System is a practice
where the victorious party rewards its supporters with government jobs or
appointing them to government positions. It was the ‘norm’ from the Presidency
of Andrew Jackson right up to the end of President’s Garfield’s administration.
Well, President Garfield was killed by a man named Charles J. Guiteau, a
mentally-ill man who believed he had helped the president win the election and
so expected to be rewarded. Guiteau was not given a gov’t post and so plotted
to kill the president and was successful. The assassination helped usher Civil
Service Reform in the country.
It was not true of the Confederacy during the Civil War that "<span>(D) It was plagued by large slave uprisings," since in fact there were relatively few slave uprisings in the South during the War itself. </span>
