We now load an alternative version of the submodel.

This new submodel also has a variable called "Soil water" (though in
this case it is a Simile variable, not a compartment), and a flow called
"transpiration". Note also that this submodel is structurally different
from the first submodel: all that matters for plug-and-playability is that
the two models have the same interfacing variables: the rest of their
structure is irrelevant.

At this stage, the linkages are not re-made. The Soil submodel contains
an unsatisfied input parameter
"Plant biomass", while the main model contains an unsatisfied input
parameter called "Soil water". These undefined elements are shown in
red.
In: Contents >> Working with submodels >> Plug-and-play modularity