John Dalton revolutionized science in 1803 when he hypothesized that atoms of different chemical elements, such as hydrogen and oxygen, had different characteristic masses. J.J. Thomson discovered the first subatomic particle -the electron - in 1897.
The aim of biology is to explain the living world in terms of scientific principles. Aristotle, the great Greek philosopher and teacher, is known as the father of biology and the French naturalist, Jean Baptiste-de Lamarck, was the first to used the word ‘biology’ in 1800.
Its average weight is about 340 grams in men and 255 grams in women. The left half and the right half of the heart is divided by a wall called septum. Each half, in turn, is divided into an upper chamber called the auricle and a lower chamber called the ventricle.
Cells are the basic units of life. They are the smallest parts of a living organism that can lead an independent existence. Singly, or in association with other cells, they make up the bodies of all living things.
The French biologist Lamarck proposed, in 1809, a hypothesis to account for the mechanism of evolution, based on two conditions: the use and disuse of parts, and the inheritance of acquired characteristics.
Blood consists of a faintly yellow fluid, the plasma or liquor sanguinis, in which are suspended numerous minute particles, the blood corpuscles, the majority of which are coloured and give the blood its red tint.