Which bond should be
more stronger , C-C or C=C. why?

carbon - carbon double bonds are stronger . More is the overlapping , more stronger a bond is. Hence, carbon - carbon double bond is stronger than single bond.

Hey mate hope its help you

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.