Why was duct tape invented?

Working principle of differential thermal analysis? If you cannot restart your computer when you are following the instruction of the program does it damage the program if you shut down and switch back on? What are 5 equivalent fractions for 1.10? Is a lawn sprinkler a Compound Machine? Write a program in c plus plus to accept the string and then take the starting and ending point from the user and display the sub string through function? How does technology make the world better in around the world in 80 days? Is dc voltage the same as millvolts? What are the advantages of using graphical endpoint compared with visual enpoint? Why was the Bessemer converter important? What is ic dexamethasone? What is platform dependency of c plus plus? Why are engineering and medicine the best professions? What is a type of metal block for securing a railway rail to sleeper? Are all globe valves directional? What is current divider rule and voltage divider rule? Where garbage is disposed of by being buried under a shallow layer of soil? What can be arranged in a visual display to make identifying trends easier? Write a program to find the grade obtained by the students of a class using structure? What happens when motor coupled with genarator? What is the sIZe for schedule 40 black iron pipe?

Why was duct tape invented?