i) Dew is a water droplet formed by the condensation of water vapour on a relatively cold surface of an object
ii) It forms when the temperature of an object drops below the dew point temperature.

i) An aquifer is an underground layer of water - bearing permeable rock, rock fractures or unconsolidated materials (gravel, sand or silt).
ii) Ground water can be extracted using a water well.
iii) The study of water flow in aquifers and the characterization of aquifers is called hydrogeology.

(i) Runoff is the water that is pulled by gravity across land's surface. It replenishes ground water and surface water. 
Runoff is also a major contributor to the erosion which carves out canyons, gorges and related landforms.
The run off may be classified into following three types
i) Surface runoff
(i) It is the portion of rainfall, which enters the stream immediately after rainfall.
(ii) It occurs when the rainfall is longer, heavier and exceeds the rate of infiltration.
(iii) In this condition, the excess water makes a head over the ground surface, which tends to move from one place to another following land gradient and is known as overland flow.
ii) Sub-surface runoff
(i) The water that has entered the subsoil and moves laterally without joining the water-table to the streams, rivers or oceans is known as sub-surface runoff.
(ii) The sub-surface runoff is usually referred as inter flow.
iii) Base flow
(i) It is a flow of underground water from a saturated ground water zone to a water channel.
(ii) It usually appears at a downstream location where the channel elevation is lower than the ground water table.
(iii) Ground water provides the stream flow during dry periods of small or no precipitation.

Sometimes rain drops fall through a layer of air below OOC, the freezing point of water. As they fall, the rain drops freeze into solid particles of ice. So, the mixture of water droplets and ice particles would fall on the earth surface.

Water entering the soil at the surface of the ground is termed as infiltration. It allows the soil temporarily to store water, making it available for plants use and organisms in the soil.