.... may arise as to how exactly this disease is spread from person to person and what conditions promote infection. For example, one may wish to investigate the following: 1) Mycobacterium leprae as yet to be cultured in laboratory media? Why? 2) Why is leprosy so prevalent in some parts of the world (i.e. India) but not in others? 3) How does leprosy become so widespread in a population? 4) Despite the discovery of drug treatments, why are over million people still infected? 5) Is there a genetic predisposition to leprosy? 6) Are there non-human sources for the disease? .....

.... were homosexual or bisexual men; but now there are many infections seen among heterosexual men and women. Heterosexual sex is now the main method of transmission in Singapore and over 75% of infections throughout the world are acquired through heterosexual intercourse. Not everybody who has sex with an infected person will get infected. However, the risks increase sharply in the presence of other Sexually Transmitted Diseases (STD) i.e. gonorrhea, herpes and syphilis or when the infected person has symptoms of late HIV infection. Females have an eight times greater ris .....

.... an iron core extending outwards 4/5 of the way to the surface. Mercury bares a very similar resemblance to our moon because it has a lot of craters. The craters, which cover seventy-five percent of Mercury’s surface, were formed by huge rocks that smashed into the planet’s surface. The largest crater is called the Caloris Basin and it is 1400 km in diameter and is flooded with molten lava. Mercury also has many cliffs that are usually over 300 miles long and two miles high. The rest of the planet’s surface is smooth and may have been formed by lava flowing out of cracks .....

.... from the culture of a single cell of a certain type, such as a human fibroblast or a rodent-human hybrid cell containing a full set of rodent chromosomes and a single human chromosome. Human embryo cloning starts with a standard in vitro fertilization procedure. Sperm and an egg cell are mixed together on a glass dish. After conception, the zygote (fertilized egg) is allowed to develop into a blastula (a hollow mass of cells). The zygote divides first into two cells, then four, then eight... A chemical is added to the dish to remove the “zona pellucida” covering; this materi .....

.... 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 genetically engineered to grow larger and at a faster rate. According to U.S. News and World Report, many pharmaceutical drugs, including insulin, are already genetically engineered in the laboratory. Many enzymes used in the food industry, including rennet used in cheese production, are also available in geneticall .....

.... gases and others become tiny specks of ash. As these chemicals drift, they may change again. They may react with other chemicals in the air. When sulfur dioxide combines with water, the result is sulfuric acid. When nitrogen oxide gas combines with water, the result is also another acid. When the clouds releases rain or other precipitation, the acid goes with it. This is called acid rain. The level of acid is measured in pH levels. The pH scale begins at 0 and ends with 14. A reading lower than 7 is called acidic, and a reading higher than 7 is called basic. Seven is ne .....

.... it can even be found in saliva cells left on a mouthpiece of a telephone after a conversation. DNA is everywhere in a persons body, and can not be replicated. It is unique to every person, but all blood relatives have similar qualities that make them identifiable. (Joe Mickel and John F. Fischer, 1998) DNA stands for deoxyribonucleic acid, and it basically looks like a twisted ladder, or a double helix with rungs or base pairs. Guanine (G), Adenine (A), Thymine (T), and Cytosine (C) are the four bases that make up the base pairs. The bases don't just pair with any ot .....

.... understanding of electricity. A third idea was that if the distance between electric charges is increased, the force of attraction or repulsion decreases. All matter is made up of very tiny particles called atoms. Atoms are made up of even smaller substances called subatomic particles. Scientific studies have found that some of these subatomic particles are charged with electricity. The electric charges are made up of two kinds - positive and negative. The positively charged particles are called protons, and the particles with negative charges are called electrons. In an atom, .....