Question about the enclitic "-ne"

Nutting exercise 37; English into Latin–“Are there apples on the tree? Do you see berries in the garden?”
The key translates this as “Suntne mala in abore? Bacasne in horto vides?”. Why does the verb “sunt” take
“ne” while “vides” dosen’t? A&G says -ne is added to the emphatic word. This sounds a little subjective. Why is sunt more emphatic than vides. Is there more to the rule or is this a subjective free for all?

The emphatic word is the first.

Videsne bacas in horto? would be perfectly fine.

To clarify, -ne is always attached to the first word of the sentence, whatever that word may be.

It is subjective, and the key only offers one possible translation. Latin (in its written form) is more expressive in asking questions. English does this orally by stressing a word:
Bacasne in horto vides? do you see berries in the garden?
In hortone bacas vides? do you see berries in the garden?
Videsne bacas in horto? do you see the berries in the garden?
Tune vides bacas in horto? do you see berries in the garden?

Thank you very much bedwere, Barry, and Nesrad for answering my question.