#2 and #4 mean the same. You will hear both 'is' and 'are' used as the verb (click HERE for a discussion about that).1. There are green and red apples in the box.
2. There are a green and a red apple in the box.
3. There are a green and red apple in the box.
4. There is a green and a red apple in the box.
5. There is a green and red apple in the box.
#3 is ungrammatical—there is only one apple: it's a two-colour one.
#1 is ambiguous: we don't know whether the apples are all green, all red, partly green and red, or a mixture of the three.
#5 is fine: there is one two-toned apple in the box.
Please note that 'Thread titles should include all or part of the word/phrase being discussed' (Posting Guuidelines). 'Green and red apples' would have been a good title for this.
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