In India, National Income is calculated by the combined method. It combines two methods i.e product or output method and the income method. This is done to overcome the problem of deficiency of statistics. The product method endeavours to find out the net contribution to national income of all producing units. The income method adds up income and payments accruing of factors of production. This method is used in the tertiary  sector like government services banking etc and also in the commoity sector if output data is not available.

Basically India's unemployment is structural in nature. It is associated with the inadequacy of the productive capacity to create enough jobs for all those able and willing in india. Not only is the productive capacity  (largely capital stock) much below the needed quantity, it is also found to be increasing at a slow rate. As against this, additions to labour force are being made at a fast rate on account of rapidly rising population. Thus, the absolute level of unemployed persons is rising every year. 

Income easticity of demand measures the responsiveness of demand for any goods to changes in income. With increase in incomes generally the demand for farm products like rice wheat etc, will not change drastically. With income increase, demand for luxuries such as consumer durables etc will increase. The income elasticity  of demand for farm products is thus low.

Trypanasoma is a protozoan animal. It lives as a parasite in the blood and later invades the cerebrospinal fluid to cause the sleeping sickness. This parasite is transmitted by the Tsetse fly.

The hormone adrenaline also called epinephrine is known as a stress hormone. In emotional upsets( like fear, anger etc.) this hormone is poured into the blood and it accelerates heart beat. The hormone acetylcholine decelerates heartbeat rate.

The blood of some invertebrate animals like the earthworm is red due to haemoglobin pigment, but the pigment is dissolved in the plasma. In vertebrates the same pigment is found in the red corpuscles and not in the plasma.

Passivity of iron is due to formation of an extremely thin and impervious film of ferrosoferric oxide Fe3O4on the surface of iron. Chromic acid, being a powerful oxidising agent (like nitric acid ) renders iron passive. 

A 40% solution of Formaldehyde known as Formalin is used in the preservation of biological specimens because of its hardening action on proteins.