Officially two words, but consider "afterwhich" an acceptable misspelling.
2 words
Animals eat the apples and then move around, afterwhich they poop the seed out.
It should be 2 words.
Animals eat the apples and then move around, afterwhich they poop the seed out.
2
Into is 1 word.
Green Day is 2 words.
I is 2 words. SPRAY-BUTTER
Two words.
1
No, one thing can be 1 or 2 words e.g NERVE_CELL. 2 words, 1 thing.
2 words.