Alkanes are saturated hydrocarbons. Saturated means that the hydrocarbon has only single bonds and that the hydrocarbon contains the maximum number of hydrogen atoms for each carbon atom.

The process of absorbtion of rain water by the soil on the earth is called infiltration. By this process, the rain water that falls on the soil becomes ground water.

There are many isotopes of uranium and all of them have same atomic number i.e, sum of nmber of neutrons and protons.

Chemical weathering is the process of altering rocks chemically when they are broken down. It includes hydrolysis, oxidation, acid rain, etc...