How change “from” email address for Buddypress activation emails?

When a new user signs up to the Buddypress social network, they receive an email from my website saying that they need to activate their account. I have two questions:

1) How do I change the “from” email address for the activation email? Currently it is coming from root@localhost.  I would like it to be hello@mydomain.com

2) After clicking on the activation link in the email the user has to click on an activation key. I have never seen anything like this. Is this how it is supposed to be? See attached.

Thanks!