... Aquatic animals use gills, which are outgrowths from the body which increase surface area over which gas exchange can occur. Inside the gills of aquatic animals, the circulatory system removes oxygen, and delivers waste carbon dioxide. Land vertebrates have developed a different approach to the problem of gas exchange, as water is not present in all of the terrestrial environment. Terrestrial vertebrates have developed lungs to solve this problem. Air enters through the nasal passages, or the mouth, passes through the trachea, then branches off at the two bronchi, and goes through many branching passages called ...

... Prize-winning biologist and Harvard professor, said that most of the now being used commercially is in the agricultural sector. Plants are genetically engineered to be resistant to herbicides. Insects are being genetically engineered to attack crop predators. Wald noted that research is ongoing in growing agricultural products directly in the laboratory using genetically engineered bacteria. Genetically engineered animals are being developed as living factories for the production of pharmaceuticals and as sources of organs for transplantation into humans in the United States and abroad. Fish are being genetica ...

... environmental and health implications involved. A key step in the policy-making process is to define the problem to be remedied. If we can not understand the problem, how are we to know what needs to be fixed. Unfortunately, implementing policies on air pollution has the politically undesirable effect of having extensive economic consequences on all sectors of the economy. Therefore, those policies which lead to the development of an ecosociety must be aimed at having the greatest environmental impact while creating minimal economic distortions. For the purpose of this essay, pollution sha ...

... through the burner. Then take a lighted match over the side to light it. Don’t allow any air when you are lighting the burner. When it is lit you will see a yellow flame. Then you would take the evaporating dish and put it in the flame for a few minutes. To see what would be collected on the dish. after you do that. Then you turn the barrel until you can’t see the yellow flame anymore. Then put the dish in the hottest part of the flame and see what happens. After you do that. You would cut off the burner by closing the needle value and closing the barrel. Then you would cut off the gas. In the conclusion the ho ...

... cause of these deaths. They suspect that the Red Tide off of the coast of southwest Florida has some connection with these mysterious deaths. A red tide is a bloom of flagellates which are deadly to marine life, but cause no harm to the human population. Another possible cause is a virus that is unknown to scientists. Many people believe that this problem will eventually stop an the manatee population will flourish, but others are rather pessimistic. Ecological Problem: The manatee population is quickly dying off and unless they make an astonishing comeback, they will soon be extinct. Ecological Solution: ...

... and bones shortly under the surface of the Earth. After scientists got more into the study they started to dig deeper down. The fossils get so deep because of the years of rocks and dirt that were piled up on it. Some also get buried if a dinosaur were to die next to a river, and over the years the river probably changed courses a little, so therefore the bones would be covered up. They would actually be in the bank of the river. The Evolutionary theory states that everything evolved over millions of years. Evolutionists say that dinosaurs came from six million years back. They also say that the Earth is fou ...

... chemicals in air pollution that create are sulfur dioxide and nitrogen oxides. usually forms high in the clouds where sulfur dioxide and nitrogen oxides react with water, oxygen, and oxidants. This forms a mild solution of sulfuric acid and nitric acid. Sunlight increases the rate of most of these reactions. Rainwater, snow, fog, and other forms of precipitation containing those mild solutions of sulfuric and nitric acids fall to the earth as . Water moves through every living plant and animal, streams, lakes, and oceans in the hydrologic cycle. In that cycle, water evaporates from the land and sea into the atm ...

... Completing the scientific investigation and licensing of the Yucca Mountain site is expected to cost $6-7 billion alone. At the end of 1993, total nuclear waste fund expenditures through the end of the year were nearly 3.7 billion. Very little of this money comes from individual investors. If a retrievable facility (one where the casks of spent fuel can be retrieved later) is built, this will be a good deal more. Other disposal types, such as sub- seabed and space disposal may prove to be cheaper at a later time. This is a cause for concern, but there are a greater amount of reasons to further and eventua ...

... X and Y chromosomes. "What we're trying to decide now is whether to isolate probes for the other chromosomes, or whether we should utilize the eight we have," he says. Dr. Willard is currently negotiating with an American company to develop prenatal diagnostic tests, which, because the current tests are time consuming and technically difficult to do, are restricted to women over 35 and those who have a family history of chromosomal abnormalities. Prenatal tests using Willard's probes would be much simpler and faster to perform and could be available to all pregnant women who wish to take advantage of the ...

... climate are not accurate. The supporting measurements are taken from the surface. These readings do not cover enough of Earth's surface to be considered accurate. Also, even if they covered 100 % of the ground temperature 70 % of the Earth is water so the readings would still not be acceptable. Orbiting satellites cover 99 % of the Earth's surface. According to surface-based temperatures, 1997 was the warmest year on record. According to U.S. government satellites and weather balloons1997 as the seventh coolest year since satellite measurements began in 1978. Further more, satellite and balloon based inform ...