The most abundant source of methane in the globe is coal-fired power plants.
Hypotheses must be provable. If scientists cannot prove a "hypothesis" right or wrong, they need to change it to a legitimate hypothesis - something you can prove.
If it is proven wrong, they can change certain aspects of it to make a more specific experiment.
<span>Simple.
All of the millions of different life forms (the diversity of life) have come about by natural selection, whereby random mutations in the genes have either succeeded or failed.
But all life can be traced back to a common single-celled origin. Thus we have the unity of life where we (possibly) share more than 50 % of our DNA with a crocodile.eg:analogous organs, homologous organs.</span>