.... theory of Plate Tectonics has evolved from and replaced Wegener's original thesis. Plate Tectonics is the theory that deals with the structure, history, and dynamics of the earth's crust. The earth's crust is formed of 13 continental plates. The boundaries of the zones are where tectonic activities occur, and where earthquakes and volcanic eruptions tend to happen. The plate tectonics theory was thought up in the 1960s and 1970s, with ideas taken from Wegener’s earlier thoughts. Earlier, Wegener and other scientists had noted that continental crust grow .....

.... This is referred to as a singularity. When this happens, escape would require a velocity greater than the speed of light. No object can reach the speed of light. The distance from the black hole at which the escape velocity is just equal to the speed of light is called the event horizon. Anything, including light, that passes across the event horizon toward the black hole is forever trapped. Using a small black marble as an example to represent the size that the Earth would become if it collapsed and became a black hole, Todd R. Lauer, of the National Optic .....

.... food on the food chart. Without them many heterotrops would die from starvation. 3. Why did you put your syringes containing leaf material in the dark prior to illumination? The reason this was done was to make sure as little oxygen as possible was contained in the leaf material. This coused the experimrnt to run properly. If the leaf material was not placed in the dark, the dark reaction would not have occured using up all the oxygen. If there was still oxygen in the leaf material, the data collected would have been off. The reason for this is that the lea .....

.... extending back 160 000 years. Through the ice sheet, we know that 160 000 years ago, carbon dioxide concentrations were about 180 ppm and have presently exceeded 350 ppm. 5) There are mainly 3 major sources of carbon dioxide presently and historically. They are industrial activity, land use change and cement plants. The carbon dioxide from industrial activity mainly comes from fossil fuel burning and is by far the most abundant of sources. The carbon dioxide from land use change comes mostly from deforestation which occurs mostly in Brazil, Indonesia a .....

.... to inject drugs; hemophiliacs (persons with a blood-clotting disorder) and others who had received blood transfusions; females whose male sexual partners had AIDS; and the children of parents with AIDS. However since 1989, heterosexual sex was found to be the fastest growing means of transmission of the virus, with 90 percent of the new cases coming from heterosexual sex. How AIDS Is Spread AIDS is transmitted by direct contact of the bloodstream with body fluids that contains the AIDS virus, particularly blood and semen from an HIV-infect .....

.... invent to satisfy their curiosity of their urge to create (7,364/5), but satisfying economic needs, was one of the main reasons for invention. The economic inventions needed were devices, machines, business, and industry-processes and products. The majority of economic inventions collaborate with one another; a lot of things were invented to make other inventions work. Another major reason people invent is to satisfy military needs. During war times engineers, scientists, and inventors are brought together and their only duty is to invent military weapons. Th .....

.... There are various kinds of dynamics of macroevolution. Punctuated equilibrium theory proposes that once species have originated, and adapted to the new ecological niches in which they find themselves, they tend to stay pretty much as they are for the rest of their existence. Phyletic gradualism suggests that species continue to adapt to new challenges over the course of their history. Species selection and species sorting theories claim that there are macroevolutionary processes going on that make it more or less likely that certain species will exist for .....

.... as inheritable traits. This generalized hypothesis of evolution by acquired characteristics was not tested scientifically during Lamarck's lifetime. A successful explanation of evolutionary processes was proposed by Charles Darwin. His most famous book, On the Origin of Species by Means of Natural Selection (1859), is a landmark in human understanding of nature. Pointing to variability within species, Darwin observed that while offspring inherit a resemblance to their parents, they are not identical to them. He further noted that some of the differenc .....