.... to communicate with one another by passing small molecules from one cell to another. Groups of two or more tissues that function together make up organs. An organ system is a group of organs that work together to carry out major life functions. Eukariotic Cell Structure: Boundaries and Control: Plasma Membrane - The plasma membrane is sometimes called the cell membrane, or the cellular membrane. It is the outermost part of the animal cell, and it's purpose is to enclose the cell, and change shape if needed. The cell membrane is capable of allowing materials to enter and exit the cel .....

.... researchers found that salt imbalance caues thick mucus to accumulate in the patients lungd. High level of salt in lung cells draw water out of the mucus causing it to thicken.The level of salt in a cell is determained by the movement of ions across the cell membrane.Ions are carried across call memebranes by protein channels embedded in the cell membrane. Since the stucture and functions of proteins are determained by genes problems with ion transport can be assumed to have a genetic basis. In 1989 an American Canadian research team found thre defect in the gene called the transmembrane .....

.... to give weak hormone activity. These doses are not likely to be encountered in the environment. However the process of bioaccumulation can result in top-level predators such as humans to have contaminants at levels many million times greater than the environmental background levels (Guilette 1994). In field studies, toxicity caused by endocrine disruption has been associated with the presence of certain pollutants. Findings from such studies include: reproductive disruption in starfish due to PCBs, bird eggshell thinning due to DDT, reproductive failure in mink, small penises in alligators .....

.... explained as; there is only so many resources and as population increases those resources will soon be depleted. Ehrlich uses historical population research to lead to the conclusion that in 90 years the population could be well over the earths carrying capacity. In third world countries where population control is rarely used population, pollution, and scarcity are becoming ever increasing problems. Roughly 40% of the population in third world countries are children 15 years or older. Ehrlich explains that if population growth continues at this rate older generations will find themselve .....

.... photosensors, strain gages, solar cells, charge transfer devices, radiation detectors and a variety of other devices. Silicon belongs to the group IV in the periodic table. It is a grey brittle material with a diamond cubic structure. Silicon is conventionally doped with Phosphorus, Arsenic and Antimony and Boron, Aluminum, and Gallium acceptors. The energy gap of silicon is 1.1 eV. This value permits the operation of silicon semiconductors devices at higher temperatures than germanium. Now I will give you some brief history of the evolution of electronics which will help you unders .....

.... a required ingredient in gasoline, the EPA failed to consider a basic chemical property of MTBE and its long-term effects upon the environment. Because MTBE is highly water-soluble, it dissolves in water, leading to higher concentrations of MTBE in many lakes in the California Sierra Nevada mountains and in many groundwater supplies. Hence, by addressing only one component of a system separately, the EPA failed to see the ramifications of our apparent solution. This myopic approach to environmental remediation commonly subverts our good intentions to solve environmental problems and demonst .....

.... botanist, Schwann proposed the cell theory. The cell theory has three parts: 1. All organisms are composed of cells. 2. Cells are the basic units of structure and function in organisms 3. All cells come from preexisting cells. The impact on science was very great due to the discovery of cells and the cell theory. Many or all things were effected by the discovery of cells, everything was looked upon in a different way. Some people still did not believe that all living organisms were made of tiny microscopic chambers called cells. Many people thought that people that believe .....

.... Some people now believe that this great plague was really Ebola. The first recorded outbreak of the Zaire string of the Ebola virus was in Zaire, in 1976. The doctors didn't know how to treat it and that meant that they didn't know how to contain it either. As infected people met in public places the virus spread. In Western Sudan, the same year, the Sudan string of the Ebola virus emerged with similar results. Both casts together had about a total of 550 infections and around 340 deaths (about 60% death rate). The virus' then lay dormant till 1979, when Sudan was again hit w .....

.... evolve or change in time. There was no beginning in the past, nor will there be change in the future. This model assumes the perfect cosmological principle. This principle says that the universe is the same everywhere on the large scale, at all times. It maintains the same average density of matter forever. There are observational evidences found that can prove the Big Bang model is more reasonable than the Steady State model. First, the redshifts of distant galaxies. Redshift is a Doppler effect which states that if a galaxy is moving away, the spectral line of that galaxy observed .....

.... and the Rocky Mountains. During the Neogene, the modern world took shape. The global ecosystems acquired their present configuration and prominent topographic features assumed the forms we are familiar with today. No mass extinction marked the transition from the Paleogene to the Neogene. During the 24 million years of the Neogene, however, life ad Earth’s physical features have changed significantly. The most far-reaching biotic changes were the spread of grasses and weedy plants and the modernization of vertebrate life. Snakes, songbirds, frogs, rats and mice expanded dramatica .....