"My grandparents are farmers."
Translation:I miei nonni sono contadini.
The article must be omitted only for singular unmodified close family members: "nonni" is plural, so the article is needed. For the same reason it's "il mio nonnino" (diminutive, as affectionate form), and "il mio nonno inglese" (my English grandfather) as the noun is modified internally or externally.
You can, and in this case is probably preferable since you typically use fare to indicate your current occupation, and essere for the profession that you're trained in but not necessarily working in at the present time.
I need help with the distinction between "agricoltori" (which I thought meant "farmers") and "contadini," which I believed meant "peasants'). I answered "agricoltori," and was marked incorrect.
they both mean farmers, but I believe the whole sentence with "agricoltori" was marked wrong since it says "gli miei nonni sono..." when it should be "i miei nonni sono..."
Why is it "i miei nonni" in this sentence while before I had a sentence in which "il mio zio" had to be without "il"?
You don't use "il" or "la" for a singular immediate family member, but you need "i" and "le" for plural. E.g. sing. "mia sorella", pl. "le mie sorelle"
Because lo/gli is only for when the next word starts with a consonant cluster (squalo, stivali), z (zucchero), or a vowel or glide (yogurt, uomini).
Presumably 'I miei nonni fanno i contadini' would also be an acceptable translation?
"I nonni sono contadini" should be accepted too, I think, because in italian the possessive adjective is often unspoken. Ex : "Vengo colla moglie", rather than "Vengo colla mia moglie". Shouldn't it ?