18. origin of the disease\na course\nb cure\nc frequency\nd understanding\ne source
18. origin of the disease\na course\nb cure\nc frequency\nd understanding\ne source
Answer
Brief Explanations:
"Origin" means the point or place where something begins or is derived from. "Source" has a similar meaning, referring to the point of origin or the place from which something comes. The other options - "course" (the path or progress), "cure" (a remedy), "frequency" (how often something occurs), and "understanding" (comprehension) - do not match the meaning of "origin" as closely as "source" does.
Answer:
E. source