Mention suitable terms for the following statements.
(a) Decrease in density of water on decreasing temperature from `4^(@)C` to `0^(@)C` which is opposite to the normal trend.
(b) The underground layer of water bearing permeable rock present below the water table
(c ) The natural process of adding water to atmospheric air and its subsequent condensation to rain water.
(d) Type of chemical reaction carried out when electricity is passed through water.