Scavenger's Bounty

If {b} was spent to cast Scavenger's Bounty, put the top four cards of your library into your graveyard, then put a land from your graveyard onto the battlefield tapped. If {g} was spent to cast Scavenger's Bounty, search your library for a basic land card and put it onto the battlefield tapped. Shuffle your library.
If {b} and {g} were spent to cast Scavenger's Bounty, gain 1 life for each land you control.