Interchangeable parts
a. eliminated the need for human labor as machines replaced people in the factory.
c. increased production costs because more workers were needed to make each individual part.
b. meant that one machine could do various jobs.
d. reduced the need for skilled workers to produce the parts.

Read the following paragraph, and choose the best revision for one of its sentences.dr. blake is retiring at the end of the month. there will be an unoccupied office upon his departure, and it is big in size. because every other office is occupied, we should convert dr. blake’s office into a lounge. it is absolutely essential that this issue is discussed at the next staff meeting. (a) because every other office is occupied, it’s recommended that we should convert dr. blake’s office into a lounge. (b) because every other office is filled, we should convert dr. blake’s office into a lounge.