Mutation are nothing but changes in DNA sequence of cell’s genome which are caused by radiation, mutagenic chemicals, viruses and transposes and also by faults prevails during meiosis. A change in the structure of a gene resulting in an altered gene product, that is a protein, is called mutation. Most mutations have harmful effects in an organism better adapted to its environment. In that case, natural selection acts to increase the frequency of the advantageous trait leading to evolution.

This change in the structure of a gene or the genetic material DNA may be just a single base obstruction or that involving a few or more bases. A segment of DNA may be deleted in a gene or addition of a few bases in a gene may result in mutation.

Mutation can be either spontaneous or induced. The former occur due to unknown mutagenic agents present in the environment. Induced mutations are produced at will by subjecting the genetic material to a variety of known mutagens like X-rays, UV rays or some chemicals. Mutations lead to several disorders in humans which are inheritable. There are over 3000 diseases that are due to defects in single genes. But agricultural scientists make use of mutation to develop new improved varieties.

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A geosynchronous satellite will have its orbital track on the earth which will repeat frequently over points on the earth by time. If a satellite’s orbit like this lies over equator and orbit is circular, then it is called geostationary satellite. The orbits of these satellites are called as geostationary satellite or geosynchronous satellite. The further type of geosynchronous orbit is the Tundra elliptical orbit. A geosynchronous satellite will have communication network usually based on communication with or via geosynchronous satellite. A satellite that appears to be stationary in the sky is said to be in ‘geostationary’ orbit. It is launched in such a manner that it orbits the earth directly over its equator at a height of 36,000 kms. At that height, its orbital speed is such that it completes one orbit in 24 hours. Since the earth also completes one rotation around its axis in 24 hours, the satellite appears stationary in the sky from earth.

The advantage of this is that ground based communication antennas can remain ‘fixed’ pointing to the satellite and need not be turned to follow the satellite in the sky. For communication, geostationary satellites have on board transponders which receive signals from ground antennas, amplify them and send these back to be received by satellite dish antennas on ground. Power is provided on board by solar panels.

The word Endoscopy means looking inside and in general refers to looking into the human body for medical treatment using a device called endoscope. This instrument will be useful at the time of impossibility of direct line of sight observation. Endoscopy is a harmless and painless method of diagnosing diseases of any of the hollow organs of the body (like throat, stomach or intestine) by looking directly into the affected organ using a probe called endoscope. It is a hollow metallic tube fitted with a light source and a viewing system.

An endoscope will have following things in it as follows:

• A flexible or rigid tube.

• Light delivery system to light up the organ to be diagnosed or object which are going to be inspected. The source of light will be from outside the body normally and light is directed thro an optical fiber system.

• Lens system will be transmitting the image to the viewer from fiberscope.

• An extra channel which will allow the entry of medical instruments or operators.

Modern endoscopes make use of flexible bundles of optical fibers both for transmitting light to the organ and transmitting the image to the eyepiece outside for viewing.

Since the endoscope gives a direct view of the affected body parts, patients need not go for complicated investigations. Advanced endoscopes may have surgical attachments to carry out minor operations or biopsy.