How are scientific questions answered

What human activity increases beach erosion?

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u. s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?

In which phase of mitosis do the spindle fibers pull the chromosomes apart to opposite sides of the cell ?