" There is a need for a system of control and co-ordination in an organism". Justify the statement.
If the velocity of the electron is 2.19 x 10 6 m/s. Calculate the wavelength associated with it. (1) (h = 6.626 x 10 -34 Kg m 2 /s, m = 9.1 x 10 -31 Kg)