It depends on the gender of the noun you're applying the adjective to. Smaczny - m.pers, m.anim and m.inan; Smaczne - neu; Smaczna - fem
I guess being a native speaker of a Slavic language helps a bit when it comes to noun genders ('vino' in Slovenian being neuter as well), though not always (as was the case with 'obiad'). :P
Can "smaczne" mean delicious as well or is there another word for it? If smaczne does mean delicious, why wouldn't "Wine is delicious" be considered as being a correct translation?
The word for delicious would be "pyszne" and in these terms I do believe it should be accepted as an answer.
I realized that when I came to the sentence "Kanapka jest smaczna". I made the same mistake and translated it as "The sandwich is delicious". Luckily, a note popped up and said that "smaczna" is not as strong of an adjective as "pyszna" is, which means delicious as you said. I appreciate the helpful response!
Is there a trick for recognizing the gender of the noun? I assumed that wino was masculine
It's rather simple. Neuter nouns end with -o, -e, -ę. Feminine nouns end mostly with -a, -i or -ść. Most nouns which end with consonants are masculine.
while @mixhal is right this works only with nominative singular case, and there are exceptions ( some masculine -a ending nouns, some soft consonants ending feminine nouns, um ending neuter nouns,)
It's not, it's supposed to be the same vowel as most other occurences of e.
Why does it say that the answer "Wine is yummy" is incorrect. I don't know if I have not been speaking proper English all of my life, or the machine doesn't fully understand our language. As far as I am concerned, yummy means tasty.
yummy (comparative yummier, superlative yummiest)
(colloquial, lighthearted, often childish) delicious.
Which is exactly what my thought was, that it sounds kinda childish, which would look a bit inappropriate given the fact that the 'yummy' thing is wine ;). But if you really think that it should be accepted, by all means, you can report it next time you see this sentence.
As a native English speaker, I would never use yummy for wine (or any alcoholic drink)