Elements heavier than hydrogen are formed when light elements undergo nuclear fusion. fusion takes place within stars at temperatures nearing 108k. explain why this high energy is required for fusion to occur.

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.

Following are the  advantages of the parametric equations: 1) they can be used to graph curves that are not functions, like the unit circle.2) the parameter can be used to represent the quantity that is  useful to  provide us with better information about the graph.3)  it is useful to convert between rectangular equations and parametric equations.with specific reference to chemistry,  parametric equations are employ for solving hydrogen and hydrogen-like ions, quantum mechanically. herein, cartesian coordinates are converted in spherical polar coordinates. the solution obtained, when plotted on spherical polar graph paper, provides visualization of atomic orbital such as s,p,d and f. 

The answer is c.  h+  and oh−  react to form water (h2o). i just took the test and i got it right. hope this !