Your answers would be C and B.
I thinks its a layer of soil with characteristic properties, sorry if its wrong I'm a beginner
It has increasingly got hotter
Explanation:
<em>Human DNA Polymerase</em><em> </em><em>cannot be used in PCR</em><em> </em><em>beca</em><em>use</em><em> </em><em>it </em><em>i</em><em>s</em><em> adapted for a range that covers our body temperatures - a narrow range around 37°C. It can't get much above that before it starts to lose function and much below it stops having sufficient energy to move enough to react.</em>