To compare the life cycle of a tree to that of a butterfly, the most notable difference is that a tree begins as a seed. The life cycle of a butterfly, on the other hand, includes distinct stages such as egg, larva (caterpillar), pupa (chrysalis), and adult butterfly. Therefore, the most relevant response is:
A tree begins as a seed.
This response highlights a fundamental difference between the initiation of a tree's life cycle and that of a butterfly, which begins as an egg.