Final answer:
Decomposers are the organisms that break down the remains of dead plants and animals, playing a vital role in nutrient cycling within ecosystems. The correct option that describes these organisms is B) Organisms that must consume other organisms for nutrients, specifically referring to decomposers.
Step-by-step explanation:
The organisms that break down the remains of dead plants and animals play a critical role in the energy cycle and ecosystem stability. These organisms are known as decomposers. Decomposers, such as fungi and bacteria, are responsible for breaking down dead organic matter and releasing inorganic molecules back into the environment, where they can be utilized again by producers like plants in the process of photosynthesis. Organisms in this category do not perform photosynthesis and are not the same as those organisms that must actively consume other organisms for nutrients like consumers or predators. Rather, they fulfill a specific niche within the ecosystems helping in the recycling of nutrients through the breakdown of organic materials from deceased organisms, completing the energy cycle.
Therefore, out of the provided options, the correct description for organisms that break down the remains of dead plants and animals is Decomposers. This aligns with the definitions provided in the Energy Cycle and Consumers and Decomposers sections of the science texts. Hence, the answer to the student's question is option B) Organisms that must consume other organisms for nutrients, referring specifically to decomposers rather than consumers that actively hunt or graze for living prey.