http://www.cnn.com/2015/09/11/health/ancient-squirrel-leads-to-giant-virus-discovery/index.html
If a seed can survive for 30,000 years under nearly 100 feet of permafrost and used to regrow a living plant then it is possible that seeds from other worlds are present on icy comets in our own solar system hidden away waiting for the correct environment to seed their self.
If a seed can survive for 30,000 years under nearly 100 feet of permafrost and used to regrow a living plant then it is possible that seeds from other worlds are present on icy comets in our own solar system hidden away waiting for the correct environment to seed their self.