Final answer:
The most effective way to revise sentence 17 to improve sentence variety is to rephrase it as 'Other, more specific laws or policies often refer to this law as a basic guideline.'
Step-by-step explanation:
To improve sentence variety, the most effective way to revise sentence 17 would be to rephrase it as follows: 'Other, more specific laws or policies often refer to this law as a basic guideline.'
This revision maintains the meaning of the original sentence while using different wording, which adds variety to the overall writing.
By rephrasing the sentence, we avoid repeating the same structure as sentence 16 and make the writing more engaging for the reader.