STEM EXTENSION PENDING, CAN I APPLY FOR H1B

Hello,

Currently my STEM EXTENSION is PENDING with USCIS. Can I still apply for H1B?

1. If my H1B does not get picked, will my STEM EXTENSION still be valid?

2. Is this case a case of CAP-GAP?

Please explain as I am currently stuck in this situation. I really appreciate your help and response.