Why should a program close a file when finished using it?

Howard is designing a chair swing ride. the swing ropes are 5 meters long, and in full swing they tilt in an angle of 29° outside chairs to be 2.75 m above the ground in full swing.

Write a function so that the main0 code below can be replaced by the simpler code that calls function mphandminutes tomiles0. original main0 int main) l double milesperhour-70.0; double minutestraveled = 100.0; double hourstraveled; double milestraveled; hourstraveled = minutestraveled / 60.0; milestraveled = hourstraveled * milesperhour; cout < "miles" 2 using namespace std; 4 /* your solution goes here/ 6 int maino 1 test passed 7 double milesperhour 70.0 all tests passed 8 double minutestraveled 100.0; 10 cout < < "miles: " < < mphandminutestomiles(milesper-hour, minutestraveled) < < endl; 12 return 0; 13

Which best describes the role or restriction enzymes in the analysis of edna a. to break dna into fragments that vary in size so they can be sorted and analyzed b. to amplify small amounts of dna and generate large amounts of dna for analysis c. to purify samples of dna obtained from the environment so they can be analyzed d. to sort different sizes of dna fragments into a banding pattern that can be analyzed