Answer:
The given statement is true.
Step-by-step explanation:
As one goes deeper to the ground, there would be less availability of air and space for the air to come in. This signifies that the concentration of oxygen on the lower section of the excavation seems to be less in comparison to the upper ground. The deeper ground would also seem to comprise gas and oil that got developed by the millions of years’ procedure. These resources seem to be dangerous and toxic to get close by without gearing protective masks.