"Is it the last group?"

Translation: Är det sista gruppen?

[Vedun]

Why isn't it Är det den sista gruppen?

[Lundgren8]

You could also say that, but the article is optional with the adjective sist.

[cosmina805467]

Why isn't " den sista gruppen" since it is an "en ord"?

[devalanteriel]

The definite article is optional with sista, it's a little quirk. :)

[storio]

Why wasn't "förra gruppen" accepted?

[Kalzani]

That would be ' the previous group' I suppose.

[AnnemiekeR3]

Could you say
Är det här den sista gruppen?
Why counted Duolingo it wrong?

[devalanteriel]

It's fine Swedish, but det här means "this", never "it".

[Salva265354]

I do protest ! There are very few certain things in life ... one of these is the bipartition between "-en" and "-et" words in the swedish language. The word "grupp" is definitely an -en word ... ergo ....it should be "Är den sista gruppen?" and not .... "Är det sista gruppen".

[devalanteriel]

It's essentially the same thing as the det är construction, where Swedish defaults to the neuter-gender option.

You could also say är det den sista gruppen? which makes this much clearer, but it's common to skip the definite article in this specific construction.