The earth names for the 30 alien elements in order of atomic number

Iknow the answer is a but i don't know why

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.

The minerals found in bones are deposited by living cells called