der Teil = the part
nehmen = to take
to take part -- to participate = teilnehmen
Does not accept "participation". But:
"Participation is strongly recommended."
"Die Teilnahme wird dringend empfohlen."
Strongly suggest accepting the definite article in German. "The participation" even sounds inferior to me for it will hardly ever occur (as long as it is not restricted through modifiers).
The main translation will stay "the participation" (for now), though, because that's what the English-to-German exercise is automatically generated from -- this way, learners will know that they are expected to provide a translation into German with the definite article and can show that they know the correct gender of this noun.
Because that's a possible translation of Teilnahme (though in my experience, "sympathy, commiseration" is usually Anteilnahme with a prefix).
You're "taking a part" in the person's feelings, as it were, when you sympathise or commiserate with them -- you're taking a part of those feelings and making them your own.
DL really needs to be consistent...insists here on the definite article being translated, not elsewhere. Accept both and move on!