What is physical weathering NOT caused by? (pls i really need help with this!!)

What is important to study for nios grade 12 chemistry? i have only one month left.

For the following dehydrohalogenation (e2) reaction, draw the zaitsev product(s) resulting from elimination involving c3–c4 (i.e., the carbon atoms depicted with stereobonds). show the product stereochemistry clearly. if there is more than one organic product, both products may be drawn in the same box. ignore elimination involving c3 or c4 and any carbon atom other than c4 or c3.

What is the most important factor in determining climates.