In lab class, a plasmodial slime mold is used as a demonstration organism. One of the students does not understand why this organism is not considered multicellular. How would you explain it to her?

• A. The distinct cells that make up the plasmodium do not cooperate, so they do not represent a truly multicellular organism.
• B. Plasmodial slime molds are not able to reproduce sexually; therefore, they are not truly multicellular.
• C. Multicellular organisms are seen only in the kingdoms Animalia and Plantae.
• D. The nuclei found in the plasmodium of a plasmodial slime mold are diploid.
• E. The plasmodium is undivided by membranes and contains many diploid nuclei; therefore, it is not technically multicellular.

Answer: (E)

Verified step by step guidance

1. Begin by explaining the concept of multicellularity: Multicellular organisms are composed of multiple cells that are organized into tissues and organs, with cells working together in a coordinated manner.
2. Describe the structure of a plasmodial slime mold: A plasmodial slime mold is a single mass of cytoplasm that is not divided by cell membranes, containing many nuclei within a shared cytoplasm.
3. Clarify why plasmodial slime molds are not considered multicellular: Since the plasmodium is a continuous mass without individual cell boundaries, it does not fit the definition of a multicellular organism, which requires distinct, cooperating cells.
4. Discuss the role of nuclei in plasmodial slime molds: The nuclei within the plasmodium are diploid, meaning they contain two sets of chromosomes, but this does not affect the classification as multicellular or not.
5. Conclude by emphasizing the key point: The lack of cell membranes dividing the nuclei in a plasmodial slime mold is the primary reason it is not considered multicellular, despite having many nuclei.