Explain how the world would be different if C4 plants and CAM plants had not evolved.?

Question

Please help me asap. I don't understand this.

Answer 1

C4 and CAM plants both fill important ecological niches. Without C4 plants, we would not have Maize, which has contributed greatly to the size of our population. CAM plants occupy the desert regions of the world, and these regions would be even more desolate if this efficient system had not evolved.

Answer 2

Well, I don't know that the world wold be that much different, but C4 and CAM plants are a lot more efficient at converting CO2 to O2.  So I would guess that the answer that your teacher is looking for is that Global Warming would have been progressing at a faster rate over the centuries and the world would be a place mostly under water by this time in history.  I don't buy into the Global Warming as being anything more that the natural events that have been occurring since the beginning of time.  But what I have been seeing taught in schools these days, you had better go with the Al Gore theory if you want to make a passing grade.  Luck.