Why was the international system of units adopted?

What is the main reason why some developing countries fear the increase the free trade policies around the world?

Which statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.

Can someone me with 3 and 4 plz. this is for masteries test.