What change is needed in sentence 9?
Because they learned from their mistakes, that encouraged them to continue to work hard and succeed at inventing one of todays most convenient inventions, the airplane.

Change todays to today's

Delete the comma after mistakes

Change their to there

Change encouraged to encourage

Why is it economically necessary for the east germans to build berlin wall

Martin, a 32-year-old human relations administrator at a university, believes that all professors over age 50 are incapable of learning the new educational technologies and are content to keep presenting their same "tired, boring" lectures. he often expresses these views to other administrators and does not encourage any of the "older" faculty members to attend professional development meetings related to new teaching approaches nor does he suggest that the university send them to any of the technology conferences. martin is exhibiting

Why did the whiskey rebellion protest?