1 Blood Cells: The most common types of blood cells are:  red blood cells (erythrocytes). The main function of red blood cells is to collect oxygen in the lungs and deliver it through the blood to the body tissues. Gas exchange is carried out by simple diffusion.
Rutherford and Bohr describe atomic structure1913. Photo: Niels Bohr's research notes for his new atomic theory. In 1911, Niels Bohr earned his PhD in Denmark with a dissertation on the electron theory of metals. Right afterwards, he went to England to study with J.J. Thomson, who had discovered the electron in 1897.
Biographical Note for dalton Dalton, John (1766â1844), British chemist and physicist. One of the fathers of modern physical science, Dalton formulated the atomic theory of matter, a theory that established chemistry as a true science. He determined the relative weights of atoms and developed the laws of definite and multiple proportions.