Απλός is an adjective and means "simple", απλώς is adverb and means "just". Only the second one is correct.
Can you give examples because in English we might say "Just a minute " but I am guessing it is a different just. Would Greeks just say ένα λεπτό excuse the pun lol
If you follow the translation shown by mizinamo above yours and use "simply" in place of "απλώς" you'll avoid errors. Yes, "ένα λεπτό" would be the usual Gr. expression.
Is απλώς any different from απλά,
As an adverb, no. Some adverbs can take either form (edit: with -ως a bit more old-fashioned and formal), but others only one, e.g. σαφώς, γρήγορα.
The -α forms appear identical to the equivalent neuter adjectives in the plural nominative, accusative and vocative cases.
Yes, but if this were a listening exercise? It has been added to the homophones that are not to be used in listening exercise.
This is still appearing in a listening exercise (admittedly this was in the first time through the Adverbs Lesson 2, and I'd read the comments the first time it appeared in writing, so I knew what was required ...)
Thank you for your understanding. As you know this has been reported (along with other homophones) and we are waiting for it to be corrected.
"Simply" is, of course, one of the correct translations. If you are receiving a lot of rejections for correct translations you should report it as a problem.
It would help if you told us where you encountered this because when a translation that is listed as correct in our course is rejected it seems to be a technical issue. It would help if you let us know what part of the course it was on e.g. Strengthen skills, choose the right word.... Was it on the web or the phone etc.