Very small changes in size due to the wearing of a part can be detected by using a a. micrometer. b. metal rule. c. gapping tool. d. dwell gauge

Very small changes in size due to the wearing of a part can be detected by using a "A. micrometer", since this is the smallest form of measurement on the list, and would detect small changes. 

For question 1, i'm a bit stuck between serif fonts or large enough type to read. serif fonts are good fonts to use because their easy to read. but you also need your type be large enough to read. if i had to say what you need to consider most important, i would say d is the answer.  for question 3, i believe the answer is d. it seems most appropriate to do that. on every page or every other page would be too much, and only on the contact page just seems inappropriate.  for question 4, it's probably a. by "color scheme" it doesn't mean just one color, but a set of colors. colors that are complimentary to each other. having too many is too distracting so it's best to limit it as much as possible, but not to the point where your website looks dull.hope this !