Here's why:
* Adjectives describe nouns. In this sentence, the nouns are "friend", "her", "packet", and "seeds".
* None of the words in the sentence directly modify a noun to describe it. "Her" is a possessive pronoun, "friend" is a noun, "gave" is a verb, "packet" is a noun, and "seeds" are a noun.
Let me know if you'd like to try another sentence!