Final answer:
Walter committed plagiarism by presenting part or all of someone else's work or ideas as his own without proper attribution. Plagiarism is a serious offense in the academic community that can lead to damage to one's career and reputation.
Step-by-step explanation:
The question implies that Walter has committed an act of plagiarism, which is the presentation of someone else's work, ideas, or research as one's own without proper attribution.
Plagiarism can manifest in several forms, such as copying texts without quotation marks or attribution, submitting a paper written by someone else, or buying and claiming authorship of a paper from the internet.
In academia, plagiarism is a serious offense with consequences that can include damage to one's reputation and career.
Even if unintentional, acts of plagiarism can be easily avoided by engaging in careful research and adhering to proper writing practices that include correct citation and the acknowledgment of the original author's contributions.
Therefore, the best description of the kind of plagiarism Walter committed can be determined by comparing the specific actions taken by Walter in the scenario provided, to the examples and definitions of plagiarism discussed.
Whether Walter copied parts of their joint experiment write-up without quotation marks, submitted the entire paper as his own, or used ideas without giving proper credit, each would be considered an act of plagiarism.