Scientists have found two leaf fossils that come from very different climates. The smooth-edged leaf is from a warm climate, and
the toothed-edged leaf is from a forest in a cooler climate. If the toothed-edged fossil was found in the desert, what hypothesis could you draw from this information. The climate changed from cool forest to hot desert.
If the area had once been covered by ice or snow, then there would be no place to get the warm leaf from.
If the area was once underwater then I don't know how it would have grown a cold forest, a tropical forest, and then a desert.
It'd make more sense if you started with a cold forest with sharp leaves, that slowly became a warmer forest with smooth leaves, only so it could become a dessert with only leaf fossil remains.
