... a black hole. All black holes are formed from the gravitational collapse of a star, usually having a great, massive, core. A star is created when huge, gigantic, gas clouds bind together due to attractive forces and form a hot core, combined from all the energy of the two gas clouds. This energy produced is so great when it first collides, that a nuclear reaction occurs, and the gases within the star start to burn continuously. The Hydrogen gas is usually the first type of gas consumed in a star and then other gas elements such as Carbon, Oxygen, and Helium are consumed. This chain reaction fuels the star f ...

... in the past several decades. Schizophrenia is a disease of the brain that is expressed clinically as a disease of the mind. Both its symptoms and signs and its associated cognitive abnormalities are too diverse to permit its localization in a single region of the brain. The working hypothesis shared by most investigators is that schizophrenia is a disease of neural connectivity caused by multiple factors that affect brain development. (3,4,5) Our current model of the causation of schizophrenia is very similar to that used to understand cancer. That is, schizophrenia probably occurs as a consequence of multiple ...

... compounds are secreted by the body in very small amounts but are never-the-less effective in producing instinctive behavior when detected by the nose. In insects and animals, most sexual and social behavior is controlled by pheromones. Humans have used perfumes for thousands of years, but there is a basic difference between perfume and pheromones. Pheromones are produced by the body and usually do not smell at all pleasant, whereas perfumes are either synthesized or extracted from natural products and are employed because of their pleasant smell. Scientific research suggests that there are human pheromones f ...

... to feel helpless and hopeless, and blame themselves for these feelings. In some cases thoughts of death and suicide may come into play, depending on the seriousness of the depression. People who are depressed may find it difficult and become overwhelmed by simple daily tasks, which is why sometimes they withdraw from daily activities altogether. They may even withdraw from families and friends. Rod Steiger an Academy Award-winning actor who had starring roles in over 72 films is clinically depressed. During a time when Rod was down he wrote a letter to his wife and son: I want to die; I don’t want to move. I h ...

... stimulation. Electric stimulation is the application of electric current in treatment without the generation of intense heat. This includes electric stimulation of nerves or muscles, passage of current into the body, or use of interrupted current of low intensity to raise the threshold of the skin to pain. Studies suggested this therapy is applied to conditions such as ulcers, traumatic or burn wounds, osteoarthritis, and cancer. Electrical stimulation is simply the application of electrical pulses to the body, whether it is for function or therapy. The classical and common example is that of the cardiac pacemaker. ...

... by sediments washed to the sea by episodic floods, gradually eroding until the next major flood replenishes the sand. Beach formation begins as eroded continental material--sand, gravel, and cobble fragments--is washed to sea by streams and rivers. Two separate processes result in the deposit of this sand and sediment on the shore. Most sediment is suspended in sea water and transported along the coast by the longshore current, a stream of water flowing parallel to the beach that is created by the action of waves breaking at an angle to shore. Longshore transport can deliver up to a million cubic yards of sedim ...

... what happens in nature. Mayr later amended this definition to include an ecological component; “..a reproductive community of populations (reproductively isolated from others) that occupies a specific niche in nature The BSC is greatly accepted amongst vertebrate zoologists & entomologists. Two reasons account for this .Firstly these are the groups that the authors of the BSC worked with. (Mayr is an ornithologist & Dobzhansky has worked mainly with Drosophila). More importantly Sexual reproduction is the predominate form of reproduction in these groups. It is not coincidental that the BSC is less widely used ...

... Their body temperature varies, corresponding at any time with the temperature of their external environment. Endothermic animals, on the other hand, have relatively constant body temperatures. Their body temperature is independent of that of their external environment. Monkeys and walruses, for example, both have body temperatures of about 38„aC, despite living in very different habitats. However if body temperature rises above its optimum level (usually around 40„aC in mammals) then the enzyme rate inside the body will go into sharp decline. This is because enzymes are proteins, and become denatured. O ...

... also carry information. The information in the beam varies in the frequency or shape of the light wave. Because light waves are of much higher frequencies than radio waves, the have a higher information carrying capacity. In beams of light,individual photon waves are not moving along together because they are not being emitted at the same instant but instead in random short bursts. Such beams are called incoherent. The process for laser action, was first proposed by Albert Einstein in 1917. The working principles of lasers were outlined by the American physicists Arthur Leonard Schawlow and Charles Hard Townes ...

... This information is critical in understanding the history and the process of growth and change. It aids in learning about human evolution. Background: Tetrapods are creatures with four limbs, hips, shoulders, fingers, and toes, which developed sometime after lobe-finned fish, and before the first fully terrestrial vertebrates. The earliest tetrapod known is Acanthostega. It is also considered the most primitive tetrapod. It is very close to its fish ancestry, but still anatomically far from its terrestrial relatives. These creatures still lived in water, but they had a lot of the terrestrial tetrapod anatomi ...