Burdocks are common weeks with purple flowers that grow into seed heads. Each seed has a long spine with a hook on the tip. Burdock seeds catch on the fur of animals that pass by the seed heads. The animals then carry the seeds away from the mother plant and drop them in a place where they can grow without competing with relatives. There is no evidence that the seeds harm or help the animals that carry them. Which relationship occurs between burdocks and passing animals? Group of answer choices parasitism mutualism commensalism competition