Ranging poles used in farm surveying have characteristic

Decomposition of soil organic matter is mainly caused by 

The main factors responsible for rock weathering in the desert are high temperature and 

A difference between physical and chemical weathering is that

Use the information below to answer this question.
In an experiment on soil porosity, the following results were obtained:
Volume of dry soil = 52cm³
Volume of water= 48cm³
Volume of soil and water=78cm³

Determine the volume of airspace in the soil sample.