The main function of white blood cells is to help protect the human body from infection as well as other foreign materials. White blood cells are also known as leukocytes, and they develop in bone marrow from stem cells. There are five different types of white blood cells<span>, including neutrophils, lymphocytes, monocytes, eosinophils and basophils.</span>
The cell theory consists of:
1. all living organisms are made up of cells
2. cells are the basic structural/organizational unit of all organisms
3. all cells come from pre-existing cells
The two richest ecosystems lie in tropical rainforests and coral reefs. On land, tropical rainforests contain many species variation with an abundance of species in bird, mammals, amphibians, and plants. While tropical rainforests occupy only 7 percent of the Earth’s land area, they contain over half of the world’s species. This may be because species richness tends to increase with decreased elevation, increasing solar exposure, and increased precipitation; that is, hot, rainy low-land areas have the most species. In contrast, deserts have low species variation because of low precipitation. On earth, water is majorly important the equation for life. Many of the species are genetically isolated because of habitat size and variation in the build of the land (mountains, equator location, etc) such as seen in the Galapagos islands and the Amazon rainforest, both near and in South America.
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