The correct option is this: NATURE IS A SOURCE OF UNCERTAINTY AND CREATIVITY FOR HUMANS. From the passage given above, it can be seen that the author was comparing the land and the sea, drawing an analogy between them. Just as the sea surrounds the earth and can cause flooding and other disasters at anytime, so also the heart of man is surrounded by all manner of things. Thus, though nature is beautiful, it is still a source of uncertainty to man, anything can happen at anytime.<span />