Indian rupee sign

The Indian rupee sign (sign : ₹; code : INR) is the currency sign for the Indian rupee , the official currency of India . Designed by Udaya Kumar , it was presented to the public by the
Government of India on 15 July 2010, [1] following its selection through an "open" competition among Indian residents. Before its adoption, the most commonly used symbols for the rupee were Rs , Re or, if the text was in an Indian language, an appropriate abbreviation in that language.

space station

A space station , also known as an orbital station or an orbital space station , is a
spacecraft capable of supporting crewmembers, which is designed to remain in
space (most commonly as an artificial satellite in low Earth orbit ) for an extended period of time and for other spacecraft to dock. A space station is distinguished from other spacecraft used for human spaceflight by lack of major propulsion or landing systems. Instead, other vehicles transport people and cargo to and from the station. As of April 2018, two space stations are in Earth orbit: the International Space Station (operational and permanently inhabited), and China's Tiangong-2 (operational but not permanently inhabited). Previous stations include the Almaz and Salyut series , Skylab ,
Mir , and most recently Tiangong-1 .
Today's space stations are research platforms, used to study the effects of long-term space flight on the human body as well as to provide platforms for greater number and length of scientific studies than available on other space vehicles. Each crew member stays aboard the station for weeks or months, but rarely more than a year. Since the ill-fated flight of Soyuz 11 to Salyut 1 , all human spaceflight duration records have been set aboard space stations. The duration record for a single spaceflight is 437.7 days, set by
Valeriy Polyakov aboard Mir from 1994 to 1995. As of 2016, four cosmonauts have completed single missions of over a year, all aboard Mir . Space stations have also been used for both military and civilian purposes. The last military-use space station was Salyut 5 , which was used by the Almaz program of the Soviet Union in 1976 and 1977. 

VIRUS

A virus is a small infectious agent that
replicates only inside the living cells of other
organisms . Viruses can infect all types of life forms , from animals and plants to
microorganisms , including bacteria and
archaea .

Group: I–VII
Groups
I: dsDNA viruses
II: ssDNA viruses
III: dsRNA viruses
IV: (+)ssRNA viruses
V: (−)ssRNA viruses
VI: ssRNA-RT viruses
VII: dsDNA-RT viruses


Since Dmitri Ivanovsky 's 1892 article describing a non-bacterial pathogen infecting tobacco plants, and the discovery of the
tobacco mosaic virus by Martinus Beijerinck in 1898,  about 5,000 virus species have been described in detail,  although there are millions of types. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity.  The study of viruses is known as virology , a sub-speciality of microbiology.
While not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles. These viral particles , also known as virions , consist of: (i) the genetic material made from either DNA or
RNA , long molecules that carry genetic information; (ii) a protein coat, called the
capsid , which surrounds and protects the genetic material; and in some cases (iii) an
envelope of lipids that surrounds the protein coat. The shapes of these virus particles range from simple helical and icosahedral forms for some virus species to more complex structures for others. Most virus species have virions that are too small to be seen with an
optical microscope . The average virion is about one one-hundredth the size of the average bacterium.
The origins of viruses in the evolutionary history of life are unclear: some may have
evolved from plasmids —pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer , which increases genetic diversity . Viruses are considered by some to be a life form, because they carry genetic material, reproduce, and evolve through
natural selection , but lack key characteristics (such as cell structure) that are generally considered necessary to count as life. Because they possess some but not all such qualities, viruses have been described as "organisms at the edge of life",  and as replicators.
Viruses spread in many ways; viruses in plants are often transmitted from plant to plant by insects that feed on plant sap , such as aphids ; viruses in animals can be carried by blood-sucking insects. These disease-bearing organisms are known as vectors.
Influenza viruses are spread by coughing and sneezing. Norovirus and rotavirus , common causes of viral gastroenteritis , are transmitted by the faecal–oral route and are passed from person to person by contact, entering the body in food or water. HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood. The variety of host cells that a virus can infect is called its " host range ". This can be narrow, meaning a virus is capable of infecting few species, or broad, meaning it is capable of infecting many.
Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines , which confer an
artificially acquired immunity to the specific viral infection. Some viruses, including those that cause AIDS and viral hepatitis , evade these immune responses and result in chronic infections. Antibiotics have no effect on viruses, but several antiviral drugs have been developed.

WBBSE RESULT

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Evolutionary

Edit

OccurrenceEdit

Multicellularity has evolved independently at least 46 times in eukaryotes,^[5][6] and also in some prokaryotes, like cyanobacteria, myxobacteria, actinomycetes, Magnetoglobus multicellularis or Methanosarcina. However, complex multicellular organisms evolved only in six eukaryotic groups: animals, fungi, brown algae, red algae, green algae, and land plants.^[7] It evolved repeatedly for Chloroplastida (green algae and land plants), once or twice for animals, once for brown algae, three times in the fungi (chytrids, ascomycetes and basidiomycetes)^[8] and perhaps several times for slime molds and red algae.^[9] The first evidence of multicellularity is from cyanobacteria-like organisms that lived 3–3.5 billion years ago.^[5] To reproduce, true multicellular organisms must solve the problem of regenerating a whole organism from germ cells (i.e. sperm and egg cells), an issue that is studied in evolutionary developmental biology. Animals have evolved a considerable diversity of cell types in a multicellular body (100–150 different cell types), compared with 10–20 in plants and fungi.^[10]

Loss of multicellularityEdit

Loss of multicellularity occurred in some groups.^[11] Fungi are predominantly multicellular, though early diverging lineages are largely unicellular (e.g. Microsporidia) and there have been numerous reversions to unicellularity across fungi (e.g. Saccharomycotina, Cryptococcus, and other yeasts).^[12][13] It may also have occurred in some red algae (e.g. Porphyridium), but it is possible that they are primitively unicellular.^[14] Loss of multicellularity is also considered probable in some green algae (e.g. Chlorella vulgaris and some Ulvophyceae).^[15][16] In other groups, generally parasites, a reduction of multicellularity occurred, in number or types of cells (e.g. the myxozoans, multicellular organisms, earlier thought to be unicellular, are probably extremely reduced cnidarians).^[17]

CancerEdit

Multicellular organisms, especially long-living animals, face the challenge of cancer, which occurs when cells fail to regulate their growth within the normal program of development. Changes in tissue morphology can be observed during this process. Cancer in animals (metazoans) has often been described as a loss of multicellularity.^[18] There is a discussion about the possibility of existence of cancer in other multicellular organisms^[19][20] or even in protozoa.^[21] For example, plant galls have been characterized as tumors^[22] but some authors argue that plants do not develop cancer.^[23]

Separation of somatic and germ cellsEdit

In some multicellular groups, which are called Weismannists, a separation between a sterile somatic cell line and a germ cell line evolved. However, Weismannist development is relatively rare (e.g. vertebrates, arthropods, Volvox), as great part of species have the capacity for somatic embryogenesis (e.g. land plants, most algae, many invertebrates).

EARTH

Earth's mass is approximately 5.97 × 10 ^24 kg (5,970 Yg ). It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is estimated to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. [98]
The most common rock constituents of the crust are nearly all oxides: chlorine, sulfur, and fluorine are the important exceptions to this and their total amount in any rock is usually much less than 1%. Over 99% of the crust is composed of 11 oxides, principally silica, alumina, iron oxides, lime, magnesia, potash, and soda.

BLACK HOLE

Simulated view of a black hole in front of the Large Magellanic Cloud. The ratio between the black hole Schwarzschild radius and the observer distance to it is 1:9. Of note is the gravitational lensing effect known as an Einstein ring, which produces a set of two fairly bright and large but highly distorted images of the Cloud as compared to its actual angular size.