In molecular biology, the term double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA and RNA. The term entered popular culture with the publication in 1968 of The Double Helix: A Personal Account of the Discovery of the Structure of DNA, by James Watson. It was in 1901, that Austrian-American immunologist and pathologist Karl Landsteiner discovered human blood groups. Karl Landsteiner’s work made it possible to determine blood groups and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930. Edward Anthony Jenner was an English physician and scientist from Berkeley, Gloucestershire, who was the pioneer of smallpox vaccine. Penicillin is a group of antibiotics derived from Penicillium fungi. The discovery of penicillin is attributed to Scottish scientist and Nobel laureate Alexander Fleming in 1928.

Correct Option: C

In molecular biology, the term double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA and RNA. The term entered popular culture with the publication in 1968 of The Double Helix: A Personal Account of the Discovery of the Structure of DNA, by James Watson. It was in 1901, that Austrian-American immunologist and pathologist Karl Landsteiner discovered human blood groups. Karl Landsteiner’s work made it possible to determine blood groups and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930. Edward Anthony Jenner was an English physician and scientist from Berkeley, Gloucestershire, who was the pioneer of smallpox vaccine. Penicillin is a group of antibiotics derived from Penicillium fungi. The discovery of penicillin is attributed to Scottish scientist and Nobel laureate Alexander Fleming in 1928.

B-complex vitamins and vitamin C are watersoluble vitamins that are not stored in the body and must be replaced each day. These vitamins are easily destroyed or washed out during food storage and preparation. Fat-soluble vitamins — vitamins A, D, E and K — dissolve in fat before they are absorbed in the blood stream to carry out their functions. Excesses of these vitamins are stored in the liver.

Correct Option: B

B-complex vitamins and vitamin C are watersoluble vitamins that are not stored in the body and must be replaced each day. These vitamins are easily destroyed or washed out during food storage and preparation. Fat-soluble vitamins — vitamins A, D, E and K — dissolve in fat before they are absorbed in the blood stream to carry out their functions. Excesses of these vitamins are stored in the liver.

Yellow fever (also known as Yellow Jack and Bronze John) is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family. The yellow fever virus is transmitted by the bite of female mosquitoes (the yellow fever mosquito, Aedes aegypti, and other species) and is found in tropical and subtropical areas in South America and Africa, but not in Asia. The only known hosts of the virus are primates and several species of mosquito.

Correct Option: A

Yellow fever (also known as Yellow Jack and Bronze John) is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family. The yellow fever virus is transmitted by the bite of female mosquitoes (the yellow fever mosquito, Aedes aegypti, and other species) and is found in tropical and subtropical areas in South America and Africa, but not in Asia. The only known hosts of the virus are primates and several species of mosquito.

Christiaan Neethling Barnard was a South African cardiac surgeon who performed the world’s first successful human-to-human heart transplant. He performed the world’s first human heart transplant operation on 3 December 1967, in an operation assisted by his brother, Marius Barnard; the operation lasted nine hours and used a team of thirty people. The patient, Louis Washkansky, was a 54-year-old grocer, suffering from diabetes and incurable heart disease.

Correct Option: B

Christiaan Neethling Barnard was a South African cardiac surgeon who performed the world’s first successful human-to-human heart transplant. He performed the world’s first human heart transplant operation on 3 December 1967, in an operation assisted by his brother, Marius Barnard; the operation lasted nine hours and used a team of thirty people. The patient, Louis Washkansky, was a 54-year-old grocer, suffering from diabetes and incurable heart disease.

The smallpox vaccine was the first successful vaccine to be developed. The process of vaccination was first publicised by Edward Jenner in 1796, who acted upon his observation that milkmaids who caught the cowpox virus did not catch smallpox. The vaccine consists of the virus which causes the related, yet far milder, cowpox disease; this virus is named vaccinia (the term vaccine is derived from it), from the Latin vacca which means cow. This vaccine has functional viruses in it. Vaccines generally consist of a weakened (attenuated) or killed antigens, associated with a particular disease that are capable of stimulating the body to make specific antibodies to that disease. Vaccines use a variety of different substances ranging from dead microorganisms to genetically engineered antigens to defend the body against potentially harmful microorganisms. Effective vaccines change the immune system by promoting the development of antibodies that can quickly and effectively attack a disease causing microorganism when it enters the body, preventing disease development.

Correct Option: B

The smallpox vaccine was the first successful vaccine to be developed. The process of vaccination was first publicised by Edward Jenner in 1796, who acted upon his observation that milkmaids who caught the cowpox virus did not catch smallpox. The vaccine consists of the virus which causes the related, yet far milder, cowpox disease; this virus is named vaccinia (the term vaccine is derived from it), from the Latin vacca which means cow. This vaccine has functional viruses in it. Vaccines generally consist of a weakened (attenuated) or killed antigens, associated with a particular disease that are capable of stimulating the body to make specific antibodies to that disease. Vaccines use a variety of different substances ranging from dead microorganisms to genetically engineered antigens to defend the body against potentially harmful microorganisms. Effective vaccines change the immune system by promoting the development of antibodies that can quickly and effectively attack a disease causing microorganism when it enters the body, preventing disease development.