The question is in the attachment, thank you :)

Answer collision and mountain formation;

In a right-angled triangle: 1- the hypotenuse is the longest side2- we can apply pythagorean rule which states that: (hypotenuse)^2 = (side1)^2 + (side2)^2for the given triangle,longest side is 15 cm  side1 = 9 cmside2 is 12 cm  to check whether the triangle is right-angled or not,compare (15)^2 to the summation of (9)^2 and (12)^in other words, compare 225 to the summation of 81 and 144if they are both equal, then the triangle is right-angles, otherwise, it is not.you haven't provided the diagram showing her work, so i cannot tell the choice. however, apply my explanation to the question you have.

Answer music,television, corn,soybean

It's either  a. chiang kai-shek and the nationalists turned against the communists and killed hundreds of them. orb. hundreds of peasants were killed in shanghai during the period of warlord rule.  if we take into account that there was warlord rule at the time, i think that it's b (not entirely sure though)just my best thoughts.