(a)In an experiment on soil porosity, the following measurements were taken and recorded: Volume of dry soil = 50 cm³, Volume of water = 50 cm³, Total volume of soil and water = 75 cm³. Use the above information to (i) find the volume of air space in the soil sample. (ii) calculate the porosity of the soil sample. (b) Mention three reasons why soil porosity is important in agriculture. (c) State four characteristics of each of igneous and sedimentary rocks.