(February 2013) Durham tubes are used in microbiology to detect production of gas by microorganisms. They are simply smaller test tubes inserted upside down in another test tube. This small tube is initially filled with the solution in which the microorganism is to be grown.
A compound predicate is two or more simple predicates joined by a conjunction that indicate actions by the same subject. Example : Bill picked up the mail and walked the dog.. Bill is the subject for both verbs.
Compound nouns have their singular possessives formed with an apostrophe and an added s, in accordance with the rules given above: the Attorney-Generalâs husband; the Lord Warden of the Cinque Ports' prerogative; this Minister for Justiceâs intervention; her father-in-lawâs new wife.