Peeling, cutting or crushing an onion’s tissue releases enzymes called allinases which convert these molecules to sulfenic acids. The sulfenic acid in turn, spontaneously rearranges to form syn-propanethial-s-oxide, the chemical that triggers the tears. 

Chillies are valued principally for their high pungency and colour. Pungency in chillies is due to the active constituent “Capsaicin” an alkaloid which is extracted from chillies and is used to the medicine. The molecular formula of Capsaicin is C18H27NO3. 

Apiculture – Rearing bees 
Horticulture – Study of fruit and flower producing plants 
Sericulture – Rearing silk worm. 
Floriculture – Study of flowers for decoration work. 

The silkworm is the larva or caterpillar of the domesticated silkmoth, Bombyx mori. It is an economically important insect, being a primary producer of silk. It grows on leaves of the mulberry tree. 

The plant hormones are generally classified into five groups, These are : 
(i) Abscisic acid (ii) Auxins 
(iii) Cytokinins (iv) Ethylene 
(v) Gibberellins 

Quinine was first isolated in 1820 from the bark of a cinchona tree. Bark extracts have been used to treat malaria since at least 1632. 

Raman effect deals with the light rays passing through all trparent medium. According to this, a beam of light traverses a dust-free trparent sample of a chemical compound, a small fraction of light emerges in directions other than that of the incident (incoming) beam. 

It is represented by Greek letter μ(Mu). The permeability μ of the super conductor is zero. 

The earth’s magnetic field is believed to be generated by electric currents in the conductive material of its core, created by convection currents due to heat escaping from the core. 

An emulsion is a colloid of two or more immiscible liquids where one liquid contains a dispersion of the other liquids. Milk is an example of an emulsion.