The Bear population would increase due the the raise in the salmon population.
Some of the factors which dictate the choice of tests included in combination medium are:
Indole production factor
Motility factor.
Hydrogen sulfide production factor.
The test has to be compatible and also have information which is informative.
Intercellular medium and plasma are good examples of combinations of mediums which can produce a straight line of light.
Solid- Ice: 0 degrees celcius
Liquid- Water: Room temperature
Gas-Steam: 100 degrees celcius
hope this helps :)
You can locate it in a graph