A woman's orgasm begins in her clitoris, which is the counterpart of the man's penis. It is preceded by an erection of the clitoris and a moistening of the opening of the vagina. When a woman goes through a full orgasm, her uterus, vagina, anus and pelvic muscles undergo a series of rhythmic contractions. Most women find these contractions very pleasurable. Rubbing or applying other consistent pressure against the clitoris is usually needed to help the woman have an orgasm.
Orgasm plays an important role in human reproduction. It is the most exciting moment of sexual intercourse, so it is an important factor that makes men and women want to have intercourse, which allows reproduction to happen. It is also the moment at which the man releases semen into the woman to begin the process of fertilization.
During sexual intercourse, a man places his penis inside a woman's vagina and moves it backwards and forwards. The woman may also move her hips back and forth, or in a circular motion. The friction caused by this movement, together with the warmth and pressure of the vagina, causes the man to have pleasurable feelings in his penis. As intercourse continues, these feelings grow stronger and stronger until the man has an orgasm and ejaculates, at which time semen then shoots out from the end of his penis into the woman's vagina. The semen can make the woman pregnant.
The woman may also have one or more orgasms during intercourse as well. Unlike a man, who usually can have only one orgasm during intercourse, a woman may have more than one. During intercourse she may rub her clitoris, or she may have her man do so. This can make the woman have an orgasm. The shaft of the penis may also stimulate the clitoris in some positions. Scientists are not sure why women have orgasms. Some believe that the orgasm helps the sperm in the man's semen to swim up the vagina into the cervix, so that it is more likely that a sperm cell will fuse with an egg cell. Others think that the woman's orgasm is designed to help make the man reach orgasm. During her orgasm, a woman may moan, cry, or scream, which usually excites her man, and her vagina may contract, gripping the penis more tightly and making sex more exciting for him. These reactions may cause the man to ejaculate more quickly or to produce more semen; when a woman reaches orgasm during intercourse, it often makes her man have an orgasm at that point as well. Orgasm may also encourage a woman to have sex more often as it feels good, increasing the chances of pregnancy.
Prostate
The prostate is a gland of the male body that adds part of the fluid to semen. A healthy human prostate is slightly larger than a walnut. It surrounds the urethra just below the urinary bladder.
Prostate cancer is one of the most common cancers affecting elderly men in developed (also known as first world) countries and a major cause of death. Regular rectal exams are recommended for older men to detect prostate cancer early.
The prostate is often referred to as the male G-spot, which is a spot inside the female vagina that causes intense pleasure when it is stimulated. The prostate can be massaged by using a finger or during anal sex. Some males are able to orgasm with prostate stimulation alone.
Fossil
A fossil is the remains or trace of an ancient living thing.
Fossils of animals, plants, or protists occur in sedimentary rock.
In a typical fossil, the body form is retained, but the original molecules that made up the body have been replaced by some inorganic material, such as calcium carbonate (CaCO) or silica (SiO). The fossil feels like, and is, made of rock. It has been mineralised or "petrified" (literally, turned into rock).
A fossil may also be an "imprint" or "impression" of a living thing remaining in the fossilised mud of a long-gone age.
Some organisms fossilise well, others do not. The most common fossils are those left behind by organisms that produce hard materials. The hard, calcitic shells of molluscs (such as clams and snails) and of now-rare brachiopods (also known as lampshells) are examples. These sea-dwelling shellfish have produced many fossiliferous (that is, fossil-bearing) chalky layers of limestone in the earth.
Soft-bodied organisms can fossilise in special circumstances: the Ediacaran biota is a good example.
The best-known fossils for the general public are those of the giant, prehistoric dinosaurs. The fossilized bones and fossilized tracks of these huge, ancient reptiles can be seen in many museums of natural history and earth science.
The study of fossils by geologists and biologists is known as paleontology. If the study puts living things in their ecological context it is called paleobiology.
Humans have found many uses for fossils. Some fossils are found and sold for money, in Morocco, fossils of ammonites, dinosaurs and sharks are examples of such. Other fossils like those in the Tamiami formation are used in the construction of roads. In some places fossils are used as a mulch- material used to cover soil. Some fossils are used as a marker to determine formation .
Some fossils are used as a source of fuel, these fossils are referred to as a fossil fuel.
There are some sites where fossils have been found with remarkable details, or in large numbers. Palaeontologists call these sites by the German term "Lagerstätten". The La Brea tar pits in Los Angeles is such a place. So are the Solnhofen limestone quarries in Bavaria.
A very important place is the Burgess Shale, known for its many important finds
Microscopic or "very tiny" fossils are called "microfossils"; while larger, "macroscopic" fossils — such as those of seashells and mammals — are called "macrofossils". Natural stones which look like fossilized organisms, but are not fossils at all, are called "pseudofossils".
Although most fossils are formed from the hard parts of organisms, there are also "indirect" signs of prehistoric life. Examples such as a worm's trail or an animal's footprint are quite common. They are known as "trace fossils". Fossilized excrement, faeces or dung is known as a "coprolite". Chemical traces of prehistoric organisms is called a "chemofossil". Objects made by prehistoric people are called artifacts.
Even when the remains of soft-bodied animals are gone, there may be impressions, molds or carbon traces which remain permanently. So, in special cases, we do have fossils even of small, soft invertebrate animals.
Sometimes a fossil is produced as a result of dryness (desiccation), freezing, or pine resin. Mummified animals, ice-covered wooly mammoths, and insect-filled amber are examples of such fossils.
Living fossils, however, are "not" fossils at all. Instead, they are modern-day organisms which very closely resemble their prehistoric ancestors of many millions of years ago. The ginkgo tree, the coelacanth and the horseshoe crab are good examples.
Many pre-scientific peoples noticed fossils, but not all thought they were the remains of living things. Perhaps the first to leave a record of his thought was the Ancient Greek philosopher Xenophanes (about 570–470). His ideas were reported by later writers:
These ideas were rediscovered in the 17th century in Europe. Nicolas Steno in the Netherlands and Robert Hooke at the Royal Society in London both wrote and gave lectures about fossils. In the 18th century fossil-collecting began, and serious thinking on geology began to make progress. In the 19th century geology became a modern science, and fossils played a part in the theory of evolution.
Nine Inch Nails
Nine Inch Nails, or NIN, is the name of a famous industrial metal band. Trent Reznor writes all the band's songs and plays most of the music himself. He started the band in 1988 in Cleveland, Ohio, USA. Nine Inch Nails have been nominated for twelve Grammy Awards.