More than 1 service to clients

Hi sir

I have some doubts in this area

1) Is it allowed for an audit firm to provide more than one service for the client?

For ex. Providing audit

And due deligence review for same client

2) if its allowed to provide more than 1 service to same client. What are the issues here?

Is it not allowed for same team to provide more than 1 service for same client?

What else

I hope u answer each q seperately lto eliminate my confusing

Thanks v much