Final answer:
Missing forms of cited documentation are considered plagiarism because proper attribution is essential in academic integrity.
Step-by-step explanation:
Missing forms of cited documentation are considered plagiarism because proper attribution is essential in academic integrity. When a student fails to include in-text citations or a Works Cited page entry, readers are unable to differentiate the student's words and ideas from those of their sources. This violates the principle of giving credit where credit is due and can lead to accusations of plagiarism.