Some people are born with 'genetic diseases'. These are diseases because of an error or mutation in a person's DNA. An example of a mutation is cancer. Living or working in an unhealthy environment can also be a cause for diseases. Diseases are more common in older people.
Some diseases can be helped with medicine. Infections can often be cured by antibiotics, though resistance to antibiotics is a problem. Some disease may be helped by surgery. Not every disease can be helped with medicine or surgery, though. Some diseases must be treated during the whole life; they are "chronic" (long-lasting) diseases. An example of a chronic disease is diabetes mellitus. Diabetes can be treated (made better) but it can not yet be cured (made to totally go away). People who usually treat diseases are called doctors or physicians.
Some diseases that are common or very bad are tested for even in people who do not show any symptoms. If these diseases are found early they can be treated before they cause problems. An example would be checking a woman for cervical cancer with a test called a pap smear. If cervical cancer is found early it can be cured. If it is found later it usually causes death.
Another example is immunization. The basic idea is to make the body ready for a disease. The body has its own defense against disease called the immune system. One special characteristic of the immune system is its ability to remember some diseases. If a person is sick and recovers, the immune system will produce a substance called antibodies which fight the disease if it comes back to the person.
The antibody is specific to a particular disease or antigen. An example of this is measles which is a virus. A person usually a child who had never been sick with measles is given a milder form of the virus, this causes the immune system to produce antibodies against the virus. If this person is exposed to the same virus in the future, the person's immune system will remember and will fight the virus.
For general prevention to be useful:
Epidemiology is the study of the cause of disease. Some diseases are more popular for people with common characteristics, like similar origins, sociological background, food or nationality. Without good epidemiological research some diseases can be hard to track and to name. Some diseases can be taken for something else. This is why epidemiology takes a huge part in understanding how to protect ourselves against viruses, toxins and bacteria.
Carbon
Carbon is a very important chemical element, with a chemical symbol of C. All known life on Earth needs it. Carbon has atomic mass 12 and atomic number 6. It is a nonmetal, meaning that it is not a metal.
When iron is alloyed with carbon, hard steel is formed. Carbon in the form of coal is an important fuel.
A whole type of chemistry, called organic chemistry, is about carbon and its compounds. Carbon makes many types of compounds. "Hydrocarbons" are molecules with carbon and hydrogen. Methane, Propane, and many other fuels are hydrocarbons. Many of the substances that people use daily are organic compounds.
Carbon, hydrogen, nitrogen, oxygen, and some other elements like sulfur and phosphorus together form most life on earth (see List of biologically important elements). Carbon forms a very large number of organic compounds because it can form strong bonds with itself and with other elements. Because of the amounts of carbon living things have, all organic things are considered "carbon-based".
Each carbon atom usually forms four chemical bonds, which are strong connections to other atoms to form molecules. The kind of bond that carbon makes is called a covalent bond. These bonds allow carbon to form many kinds of small and large molecules. A molecule of methane is the smallest; it has four hydrogen atoms bonded to carbon. The bonds can be double bonds, meaning that two bonds form between carbon and another atom to make a stronger connection. For example, carbon dioxide has two oxygen atoms, and each one is double bonded to carbon. Carbon can even form three bonds with another atom, called a triple bond. For example, in the gas acetylene carbon forms a triple bond with another carbon atom.
By bonding to other carbon atoms, carbon can form long chain-shaped molecules, called polymers, such as plastics and proteins. Atoms of other elements can be part of the long polymer chains, often nitrogen or oxygen.
Pure carbon forms diamond by bonding to four other carbon atoms in a three dimensional crystal. It forms graphite by bonding to three other carbon atoms to form thin flat layers.
The name of carbon comes from Latin "carbo", meaning charcoal. In many foreign languages the words for carbon, coal and charcoal are synonyms.
Carbon in nature is found in three forms called allotropes: diamond, graphite, and fullerenes. Graphite, with clay, is in pencils. It is very soft. The carbon atoms in it make rings, which are on top of each other and slide very easily. Diamonds are the hardest natural mineral. Fullerenes are a "soccer ball" shape of carbon. They are mostly of interest to science. A special, man-made, tube-shaped allotrope of carbon is the carbon nanotube. Carbon nanotubes are very hard, so they might be used in armor. Nanotubes might be useful in nanotechnology.
There are 10 million known carbon compounds.
A radioactive isotope of carbon, carbon-14, can be used to figure out how old some objects are or when something died. As long as something is on the surface of the earth and taking in carbon, the amount of carbon-14 stays the same. When an object stops taking in carbon, the carbon-14 amount goes down. Because the "half-life" (how long it takes for half of a radioactive isotope to go away) of carbon-14 is 5730 years, scientists can see how old the object is by how much carbon-14 is left.
Carbon is in many places in the universe. It was first made in old stars. Carbon is the fourth most common element in the sun. The atmospheres of Venus and Mars are mostly carbon dioxide.
Carbon is important to the human body and other living things, and it is the second most common element in the human body, at 23% of all body weight. It is also a key part of many biological molecules (molecules used in life).
Most of the carbon on Earth is coal. Graphite is in many (typically desert) areas, including Sri Lanka, Madagascar, and Russia. Diamonds are rare and are found largely in Africa. Carbon is also in some meteorites.
Zaza language
Zaza language, also called Zazaki, Kirmanjki and Dimli, is an Indo-European language spoken in eastern Anatolia above the rivers Euphrates and Tigris. It belongs to the northwest-Iranian group of Iranian language. The Zaza language is related to Sangsarī, Māzandarānī, Tātī (Herzendī), Semnānī, Tāleshī, Kurdish, Persian and Balōchi. The number of Zaza speakers is not known exactly.
Chemical reaction
A chemical reaction happens when one or more chemicals are changed into one or more other chemicals. Examples:
Some reactions are fast, and others are slow. Some happen at different speeds, depending on temperature or other things. For example, wood does not react with air when it is cold, but if it is made hot enough, it will start to burn. Some reactions give out energy. These are exothermic reactions. In other reactions, energy is taken in. These are endothermic reactions.
Nuclear reactions are "not" chemical reactions. Chemical reactions involve only the electrons of atoms; nuclear reactions involve the protons and neutrons in the atomic nuclei.
In a synthesis reaction, two or more simple substances combine to form a more complex substance.
"Two or more reactants giving one product" is another way to identify a synthesis reaction. One example of a synthesis reaction is the combination of iron and sulfur to form iron(II) sulfide:
Another example is simple hydrogen gas combined with simple oxygen gas to produce a more complex substance, such as water.