Answer for capital good is B) goods used for further production (for sure, check any economic book and look in into the glossary)

nothing is more infectious than words....you r right than is used for comparison and over here we are comparing words with nothing

Answer for soil is perhaps clay....(not sure though)...it is just a logical conclusion as the other options had nothing to do with fertility.. they were just layers of soil...( i may be wrong)

For natural gas it is breathing (again not 100% sure).. i say it because people die due to suffocation when there is natural gas leakage..