The second law of thermodynamics imposes what limit on the efficiency of a heat engine?

From negative to negative

The answer which is not a detail carson used to describe the pool in the cave at low tide is b.  hundreds of periwinkles browse the branches and roots of the trees. 

Is there any opitions? if you have the periodic table, the noble gases are 8a family, the halogen are the 7a family, and the nonmetal are  carbon, nitrogen, phosphorus, oxygen, sulfur, selenium, fluorine, chlorine, bromine, iodine and astatine.