2020-09-25
Murasa Rootgrazer's middle ability doesn't count as playing a land. It can put a land card onto the battlefield even if you've already played your land for the turn.
2020-09-25
Once Murasa Rootgrazer has attacked, you can activate either of its activated abilities. Doing so doesn't remove it from combat. It remains an attacking creature and will deal and receive combat damage as normal.