The most revered branch of science is biological study. Biology is vital to society because it studies life, living organisms and all aspects of their well-being. This section of science also studies the origin, evolution, structure, function and growth of living organisms. This study deals with different aspects of life. The most studied section is the genetic one (Rebecca Johnson, 2006). Chimeras are mostly common in non-human zoology but also occur in humans although it is a rare phenomenon. This is an animal that has two or more different populations of genetically distinct cells originating from different zygotes during sexual reproduction. There are two types of chimeras that occur in humans. Microchimerism, which occurs when a small part of the body has cell lines that are distinct from other parts of the body. Tetragametic chimerism occurs when two separate eggs are fertilized by two sperm and produce two zygotes (Rebecca Johnson, 2006). Due to medical complications, organs may be moved from one body to another or to the donor site in order to replace damaged or missing ones. organs. In addition to organs, tissues are also transplanted. The organs that can be transplanted are the kidney, heart, lungs, liver, intestine, pancreas and thymus. The most transplanted organ is the kidney, followed by the liver and then the lungs. The tissues that are most commonly transplanted are the cornea and musculoskeletal grafts (Rebecca Johnson, 2006). There are differences between Darwinism and Creationism, the main areas of difference are based on data and beliefs. Darwinism is a scientifically oriented thought, it explains that living beings have common ancestors and that evolution is what gives rise to ne...... middle of paper ......n an environment is strongly determined and influenced by the state of sanitation and drinking water (Oswald Schmitz, 2007). Global warming affects the entire ecosystem while ocean acidification threatens the entire marine food chain. Ocean acidification is caused by the absorption of carbon dioxide by ocean waters. Therefore the main cause of ocean acidification is the emission of greenhouse gases, in particular carbon dioxide, as this is also the same gas that contributes to global warming (Oswald Schmitz, 2007). References Elizabeth Jones, Daniel Hartel, (2009). Analysis of genes and genomons. Retrieved from: http://books.google.co.ke Oswald Schmitz, (2007). Ecology and ecosystem conservation. Retrieved from:. http://books.google.co.keRebecca Johnson, (2006). Genetics. Retrieved from: http://books.google.co.ke