.... for diffusion: Movement of molecules from a region of higher concentration to a region of lower concentration, a vital function in the life of a cell. Like wise, the surface area and volume of a cell are directly influential in the efficiency of the cell’s nutrient absorption and waste expulsion processes. Since the cell membrane of an eukaryotic cell is its only source of nutrition, its surface area must be large enough to allow the cell’s organelles to receive the material it needs or it will die. The eukaryotic cell does this by maximizing the surface area to volume ratio. By using the surface area and volume equations for a sphere you can estimate the surfac ....

.... is caused by the predator when it stops feeding on a species lower than the predator in the food chain. So when the predator stops or reduces the amount of feeding on a species, the population of the species would start to increase. 3. It is seldom possible to count all the individuals in a given space. Explain one method by which biologists can study population densities without obtaining such data. Scientist barely ever count the amount of individuals in a certain area because it would take too much time. Instead of actually counting the number of individuals in an area they would compare it with other areas where they know the population of individuals. In this way they c ....

.... to open oceans and deeply urbanized areas. The sizes of birds range from the tiny bee hummingbird, which has a total length of two and a half inches, to the albatross, which has a wing span of eleven and a half feet. The largest bird is a bird that cannot fly, the ostrich. Ostriches can stand almost eight feet high and can weigh near 350 pounds. Other extinct birds have been measured to stand over ten feet high. The evolution of birds is still being argued. Most people believe that birds evolved from reptiles. Because of birds mainly delicate bones, few fossils have been left behind for scientists to study. The earliest bird fossils come from archaeopteryx. The fossils t ....

.... By routine, the EPA means "a near constant flow from oil rigs and derricks" (Sisskin). Nothing is ever done about the pollution, and until something is done about the oil being put into the sea, our oceans are at risk. So just how much oil is put in the oceans? According to a study conducted by the World Research Institute, "…between 3 and 6 million tons of oil are discharged into the oceans every year" (Gorman 48). To put this in perspective, that is approximately 4 football stadiums filled to the top with oil. That is just every year…and this has been going on for more than a decade. In total, 45 million tons of oil in the past ten years that have been put into th ....

.... systems of the United Stated and Japan points this out. In 1990 Americans spent 17.9 percent of the GNP on transportation, whereas the Japanese spent only 10.79 percent on transportation. This difference of nearly 7 percent, gives the Japanese economy much more money for investing in their future. Our Economy is not the only thing we should worry about, and it is also not the only thing that can be improved by the use of bicycles. There are several major problems that could be drastically reduced by the increased use of bicycles. Traffic would be a lot lighter due to the extremely small size of bicycles. It would also greatly reduce the wear and tear on our road ....

.... composed of air, earth, fire, and water—was influential in . The Roman emperor Caligula is said to have instituted experiments for producing gold from orpiment, a sulfide of arsenic, and the emperor Diocletian is said to have ordered all Egyptian works concerning the chemistry of gold and silver to be burned in order to stop such experiments. Zosimus the Theban (about AD 250-300) discovered that sulfuric acid is a solvent of metals, and he liberated oxygen from the red oxide of mercury. The fundamental concept of stemmed from the Aristotelian doctrine that all things tend to reach perfection. Because other metals were thought to be less "perfect" than gold, it was reasonab ....

.... of the airways of the lungs. This narrowing can be caused by a local inflammation of the air-ways, muscle contraction or the production of excess mucus with in bronchi. (R.Roberts, 1996) Most common is bronchial asthma. Medical definitions of asthma suggest that environmental triggers can substantially contribute to the occurrence of an asthma attack. The review of asthma in Victoria (1988) by the Asthma Foundation of Victoria outlined infection, exercise, climatic conditions, exposure to airborne irritants and emotional upsets as the main trigger factors. However, doctors use a general classification to identify a patients pattern of asthma…classifying people who ....

.... be found outside of chromosomes. It can be found in cell organelles such as plasmids in bacteria, also in chloroplasts in plants, and mitochondria in plants and animals. All DNA molecules contain a set of linked units called nucleotides. Each nucleotide is composed of three things. The first is a sugar called deoxyribose. Attached to one end of the sugar is a phosphate group, and at the other is one of several nitrogenous bases. DNA contains four nitrogenous bases. The first two, adenine and guanine, are double-ringed purine compounds. The others, cytosine and thymine, are single-ringed pyrimidine compounds. (Miller, 141) Four types of DNA nucleotides can be formed, depe ....