Knowledge: About 15 different types of cats can be bought at the local pet shop while only 10 species of spiders can be bought due to pet regulations.

Conversation:
I really like spiders, I've always had a fascination with them, do you know anything about spiders?
I do. Spiders are labeled as arthropods. They are air-breathing and have fangs which they use to inject venom. The also have eight legs.
Some people get creeped out with spiders, but not me!. Im curious though, How long do spiders live for generally?
I am not sure about the answer to that. But I know that there are at least 45,700 species of spiders.
Wow, that is crazy. Out of those, how many can I buy at the local pet shop?

Response: Hmmm, I heard only 10 are available to purchase at the local pet shop due to pet regulations.