symbiotic relationships

Currently, in our science class we've been studying symbiotic relationships. In a symbiotic relationship, at least one organism has to be helped. The three symbiotic relationships are commensalism, mutualism, and parasatism. Commensalism is when one organism is nuetral and the other is helped. An example of commensalism is a human and lice. The lice is helped by the human because it lives on the human hairs and feeds on extremely small amounts of blood drawn from the scalp and the human is nuetral because it is not harmed or helped. Mutualism is when both organisms are helped. An example of mutualism is a clownfish and a sea anenome. The sea anenome is helped by the clownfish bringing it food to survive and in return the sea anenome helps the clownfish by providing safety from other organisms. Parasatism is when one organism is helped and the other is harmed. An example of parasatism is a human and a tick. The tick is helped and the human is harmed in the symbiotic relationship they share. The human is harmed by the tick biting at the human and possibly giving the human lime disease and the tick is helped by the human giving it shelter and blood for food.

U.S. penny gets redisigned

For the past fifty years, the design of the penny has not changed. Lincoln's head has been on the front and the Lincoln Memorial on the back of the penny. Currently, the Uunited States has been working on a new design for the back of the penny. When the new penny comes out, there will be four different designs. The first design will be a log cabin because Lincoln was born in a Kentucky log cabin. The second design will have Lincoln standing in front of the Illinois State Capitol Building because Lincoln served as the Illinois state legislator and in the U.S. Congress before being elected president. Lincoln grew up on the frontier,was a rail splitter and he enjoyed reading books so the third penny has Lincoln sitting on a log taking a break and reading a book. The fourth design will has a half completed U.S. Capitol dome because of Lincoln's determination as President was to maintain the idea of a future Union during the Civil War. The U.S. is recreating the penny because of the bicentennial of Abraham Lincoln's birth and the 100th anniversary of the production of the Lincoln cent. The Los Angeles Times does not agree with the decision of redesigning the penny because they think that we should either get rid of the penny or keep the same design. They think that it has served it's purpose in America and we should get rid of it because it cost about two cents to make it and the value of the penny is only one cent.

my two resources are the following:

http://www.socialstudiesforkids.com/articles/currentevents/newpennydesigns.htm

http://www.usnews.com/blogs/new-money/2008/9/23/new-penny-shows-lincoln-reelin-in-the-years.html