I think calcium but i could be wrong
It would be B.) ospreys; decomposers
Since ospreys eat nothing but fish, if all of the trout died from a disease, the ospreys wouldn't have anything to eat because all of the fish are dead. This results in a loss of energy for the ospreys.
However, decomposers would gain more energy because they gain their energy from dead creatures, in this case, it would be the trout.
Living things are made of types of molecules, known as macromolecules.
There are four major classes of biological macromolecules:
carbohydrates
lipids
proteins
nucleic acids
Each of these types of macromolecules performs a wide array of important functions within the cell; a cell cannot perform its role within the body without many different types of these crucial molecules. In combination, these biological macromolecules make up the majority of a cell’s dry mass. (Water molecules make up the majority of a cell’s total mass.) All the molecules both inside and outside of cells are situated in a water-based (i.e., aqueous) environment, and all the reactions of biological systems are occurring in that same environment.