Making the sentence parallel, the teachers like john because
a, has been coming to class on time, participated in class discussion, and submits his assignments before deadlines.
b, comes to class on time, is participating in class discussions, and is submitting his assignments before deadlines.
c, comes to class on time, participates in class discussions, and submits his assignments before the deadlines.

Constructing an argument: in modern american society, the legalization of marijuana continues to be controversial and hotly debated. some people find it contradictory that certain "drugs"—such as tobacco and alcohol—are legalized even though they pose proven health risks, while marijuana, which has many medicinal applications, continues to be illegal by the federal government. what reasons do you think the federal government gives for outlawing marijuana, and do the reasons support the conclusion?