Infrastructure test - 9

The diseases which are more infectious called as a contagious disease. It can be transmitted through direct contact with infected person. It is also called as a communicable disease. 
Mosquitoes and other biting insects do spread diseases but not by mere contact. They need to insert their proboscis into the infected person to pick up and transmit the disease.
Contaminated food can cause the spread of disease but not by contagion. The food has to be ingested to cause the disease.
Thus, the correct answer is option D.

Food poisoning is caused either by one of a number of viruses or the bacteria Salmonella typhimurium or S.enteritidis. It is spread by contact with an infected person or via food which has been handled by an infected person. The bacterial form may also come from animals, e.g. chickens, which carry the bacteria. Whereas scurvy is caused due to deficiency of vitamin C, diabetes is a metabolic disorder caused either by insufficient production of insulin and cancer occurs when the normal control of cell division in a tissue fails. Thus, the correct answer is option B.

Hydropower plants capture the energy of falling water to generate electricity. A turbine converts the kinetic energy of falling water into mechanical energy. Then a generator converts the mechanical energy from the turbine into electrical energy.

Hydroplants range in size from "micro-hydros" that power only a few homes to giant dams like Hoover Dam that provide electricity for millions of people.

Potential energy content of wind blowing at high altitudes is that amount of energy which is present in still wind. The production of wind energy requires high wind speed with which the turbine can be rotated efficiently.

Higher speed winds are easily captured and the entire process remains inexpensive also. In case potential energy content of the wind is used for rotating the turbine the necessary outcome is not generated.

Wind speeds in the range of 6.7 to 7.4m/s or above are required to economically generate power and this is possible only when the kinetic energy of the wind is used which is then converted to mechanical energy and wind power is generated

Solar energy is the energy that is in sunlight. It has been used for thousands of years in many different ways by people all over the world. As well as its traditional human uses in heating, cooking, and drying, it is used today to make electricity where other power supplies are absent, such as in remote places and in space. It is becoming cheaper to make electricity from solar energy and in many situations it is now competitive with energy from coal or oil. A solar cooker can be used for cooking food.

Solar power plants convert sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics converts light into electric current using the photoelectric effect. Thus there is no pollution associated with harnessing solar energy.

Antibodies are chemicals (immunoglobulins) produced by certain of the white cells in the blood. They neutralize or destroy foreign substances in the blood such as bacteria or their products.

Energy- abundant, versatile, reliable, portable, and affordable, fossil fuels provide over 80 percent of the worlds energy because they are superior to the current alternatives, Disadvantage of most of the renewable energy sources is its unreliable supply. But to renewable energy resources from wind, solar, and biomass, man can control access to and conversion of the energy held in fossil fuels. Any machine or person can't control when the wind blows or at what velocity. No one can control how much of the radiant heat of the sun will hit the earth on a given day or hour.