Vitamin An organic compound which occurs in very small amounts in most vegetable matter without which normal functions may not proceed. There are many different ones and they were originally distinguished by letters of the alphabet, vitamin A, B, C, etc. Often referred to by a name indicating their chemical composition, eg. Absence of any one in the diet produces a specific syndrome. Continued complete absence can result in death.
Some animals appear to be able to manufacture their own requirements of certain vitamins.
Vivaparous Giving birth to live young, as distinct from oviparous, ie. The young undergo embryonic development in the abdominal cavity of the female. Viviparously A method of a sexual reproduction occurring in aphids by which the young are born alive and active. A toxic substance produced internally in the infected host of by the pathogen within it. Volatilisation Formation of gases.