This peculiarity is to be found in the myriad of hairlike, fibrous fingers through which the nourishment for the plant is sucked up. However, nourishment is not actually sucked up by these hairlike roots. The expression is used merely in a figurative sense. The action is entirely chemical. Water is attracted by the plant roots by the sugary content of the minute cells of which the roots are composed.
Plants take nitrogen, oxygen and hydrogen from the soil.
These are filled with a substance of very peculiar properties. From this breaking up process carbon is extracted, mixed with hydrogen. The oxygen is set free, for enough oxygen is taken in by the roots to satisfy the plant's needs. Chlorophyl is the substance that makes plants green. It is developed by the plant as needed, but it cannot be developed without sunlight, or a satisfactory, albeit inferior, substitute.