Predators may increase the biodiversity of communities by preventing a single species from becoming dominant. Such predators are known as keystone species and may have a profound influence on the balance of organisms in a particular ecosystem. Introduction or removal of this predator, or changes in its population density, can have drastic cascading effects on the equilibrium of many other populations in the ecosystem. For example, grazers of a grassland may prevent a single dominant species from taking over.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is increased by keeping a single species from being dominant in an ecosystem?
Ah, so.. biodiversity of communities

As a child, young Bell displayed a natural curiosity about his world, resulting in gathering botanical specimens as well as experimenting even at an early age. His best friend was Ben Herdman, a neighbor whose family operated a flour mill, the scene of many forays. Young Bell asked what needed to be done at the mill. He was told wheat had to be dehusked through a laborious process and at the age of 12, Bell built a homemade device that combined rotating paddles with sets of nail brushes, creating a simple dehusking machine that was put into operation and used steadily for a number of years. In return, John Herdman gave both boys the run of a small workshop in which to "invent".
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What was Bell's reward for his dehusking machine?
Ah, so.. small workshop

On December 7, 1941, Japan attacked the United States at Pearl Harbor, bringing it too into the war on the Allied side. China also joined the Allies, as eventually did most of the rest of the world. China was in turmoil at the time, and attacked Japanese armies through guerilla-type warfare. By the beginning of 1942, the major combatants were aligned as follows: the British Commonwealth, the United States, and the Soviet Union were fighting Germany and Italy; and the British Commonwealth, China, and the United States were fighting Japan. The United Kingdom, the United States, the Soviet Union and China were referred as a "trusteeship of the powerful" during the World War II  and were recognized as the Allied "Big Four" in Declaration by United Nations These four countries were considered as the "Four Policemen" or "Four Sheriffs" of the Allies power and primary victors of World War II. From then through August 1945, battles raged across all of Europe, in the North Atlantic Ocean, across North Africa, throughout Southeast Asia, throughout China, across the Pacific Ocean and in the air over Japan.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Who were the victors of World War II? 
Ah, so..
The United Kingdom, the United States, the Soviet Union and China