Why do plants need so much water and how do plants "pump" water from their roots to leaves that can be hundreds of feet high?

Plants need so much of water because, by weight most of
the weight of all plant consists of water. Further, please remember that the total water
that we may use for watering plants in a garden is not absorbed by the plants. As a
matter of fact most of the water either through watering the plants, artificial
irrigation, and natural rainfall is absorbed by the soil and through a long and
complicated process gets converted back into clouds that give us
rains.

There are some specialized methods of irrigation,
such as drip irrigation, which enable growing of plants with very limited amounts of
water by minimizing the loss of water through absorption of soil and evaporation in the
atmosphere.

The water that is present in the soil is first
absorbed by the roots of the plants through the process of osmosis. The water containing
nutrients needed by the plants so absorbed is then "pumped" or "raised" to leaves
through process of capillary action, which causes liquids to rise up in very thin tubes
or passages, called capillaries. to rise up the capillaries because of the forces of
attraction that exists between the liquid and the walls of the
capillaries.