"거미 한 마리는 눈이 몇 개 있습니까?"

Translation: How many eyes does one spider have?

[manuthchek]

"How many eyes does a spider have?" is not accepted?

[HLM1]

I think in that case you would just use the topic/subject maker after spider, and not need the counter. I'm thinking since a counter was used, a number is expected in the sentence.

[the_crait]

Same

[Akdong_]

I know, right? And I go to Korean school.

[Rymin_]

What is the use of 개 in this sentence?

[Staszek456]

universal counter. for eyes, in this case

[Strawberry806975]

It's a counter for 눈

[Rhoyelle]

Can someone please shed some light on when to use 몇 개 versus 얼마나 많이? I seem to always pick the wrong one :-/