Incorrect Word: is
Correction: are

Explanation:
The verb "is" should be changed to "are" in this passage. The subject of the sentence is plural, so the verb should also be plural to match.

Corrected Passage:
The following passage has not been edited. There is one error in each line against which a blank is given. Write the incorrect word and the correction. Explain in detail. Follow these rules.

Identifying the Errors:
Let's identify the errors and the corresponding corrections in each line of the passage.

Line 1:
The word "is" should be changed to "are" to match the plural subject "errors."

Line 2:
The word "line" is correct.

Line 3:
The word "blank" is correct.

Line 4:
The word "write" is correct.

Line 5:
The word "the" is correct.

Line 6:
The word "incorrect" is correct.

Line 7:
The word "word" is correct.

Line 8:
The word "and" is correct.

Line 9:
The word "correction" is correct.

Line 10:
The word "Explain" should be changed to "Explain in detail" for clarity.

Line 11:
The word "Follow" is correct.

Line 12:
The word "these" is correct.

Summary:
There is only one error in the passage, which is in Line 1. The verb "is" should be changed to "are" to match the plural subject "errors." The rest of the passage is error-free.

Revised Passage:
The following passage has not been edited. There are one error in each line against which a blank is given. Write the incorrect word and the correction. Explain in detail. Follow these rules.