Infrastructure - Class 12 Commerce Economics - Extra Questions

Air borne disease - Influenza, COVID-19, SARS, Swine flu, etc.

Today electrical energy generation has become the need of the hour. We cannot imagine our life without electricity. We have been able to generate electrical energy through various methods. In these methods, a generator is present which works on the principle of electromagnetic induction. A turbine is used to rotate this generator and this turbine itself is rotated with the help of an energy source. This energy source can be renewable sources such as wind, sunlight, nuclear fuels, etc. as well as non-renewable sources such as coal, petrol, water, etc. The energy sources such as wind, sunlight have proved to be green sources as they do not pollute the environment and are economical too. But the use of fossil fuels such as natural gas, coal, nuclear energy, etc. as an energy source has harmful effects on the environment. The harmful radiation emitted from nuclear waste has a fatal effect on the environment and humans. Even the release of soot particles and various greenhouse gases such as carbon dioxide, carbon monoxide on burning, or incomplete burning of fossil fuels affects the health of living beings as well as the environment adversely. Also, the release of these greenhouse gases is day by day increasing the danger of global warming. We need to as soon as possible find suitable environment-friendly substitutes to fossil fuels to save our Earth.

Chlorosis is a physiological disease, characterised by yellowing of leaves due to shortage of mineral elements like magnesium or iron, while etiolation is a physiological  enomenon shown by green plants when kept in dark. Such plants show elongation of stem with primary leaves unexpanded and yellow in colour.

Food colours are often mixed with most of the available foodstuff in the market, such as sweets, soft drinks, cakes, ice creams, meat, spices etc. These food colours are present in the form of powders, gels and pastes. They are used in domestic as well as commercial products. These food colours can be natural as well as artificial in nature. Tartrazene and sunset yellow are extensively used artificial food colours. 

Air borne diseases are those that are transmitted through air by coughing, sneezing etc. E.g: Anthrax a disease caused by the bacterium Bacillus anthracis is an example of air borne disease.

Diseases occur when our immune system is not working properly. The proper functioning of the immune system depend on the food we eat and thus when we are sick, we are advised to consume nutritious food. Bland food is food which is low on salt, sugar, oil and spices. This aids easy digestion and prevents disorders of the digestive system.

Non-conventional sources of energy are less used in the industries because a lot of problems are faced in harnessing them and storing them, besides the problems of heavy cost and management.

Electrical energy can be easily converted into many other forms.

The different ways by which housefly contaminates food are:

• Pouring saliva out - Food gets moist when housefly regurgitates on food or pours its saliva as a result pathogens get discharged on them causing the food to get contaminated.
• Hairy body and legs pick up filth - Spiny or hairy legs and body tend to pick up dirt containing germs from germ-infested places such as faecal matter, rotten material, infected wound. When these carriers/flies rest on our food, they rub their legs continuously dropping the particles of dirt on the food, causing it to get contaminated.
  
• Excreta - It deposits its excreta while it feeds, thus contaminating human food.
  
• Direct transmission of germs - Houseflies directly transmit pathogens in some cases. In case of eye disease trachoma, pathogens are transmitted from an infected person to a healthy person, when a fly settled on an infected eye of a person sits on the eyes of a healthy person. 

Industrial sector has the largest share in total consumption of commercial energy.

The completed flow chart: