Which of the following statements about biogeochemical cycles is not true?

Options

A. Most elements remain longest in the living portion of their cycle.
B. Gaseous elements cycle more quickly than elements without a gaseous phase.
C. You may have some atoms in your body that were once part of a dinosaur
D. Biogeochemical cycles all include both organismal and nonliving components.

Answer

To determine which statement about biogeochemical cycles is not true, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify the statement that is incorrect regarding biogeochemical cycles.

2. **Evaluate Option 1**:
- Statement: "Most elements remain longest in the living portion of their cycle."
- Analysis: This statement is incorrect. In biogeochemical cycles, elements typically remain longer in the non-living (abiotic) components of the ecosystem, such as soil and water, rather than in the living (biotic) components. Thus, this statement is not true.

3. **Evaluate Option 2**:
- Statement: "Gaseous elements cycle more quickly than elements without a gaseous phase."
- Analysis: This statement is true. Gaseous elements, such as carbon and nitrogen, can move rapidly through the atmosphere, making their cycles faster compared to elements that do not have a gaseous phase.

4. **Evaluate Option 3**:
- Statement: "You may have some atoms in your body that were once part of a dinosaur."
- Analysis: This statement is true. Atoms are recycled through various biological and geological processes, and it is indeed possible that some atoms in our bodies were once part of ancient organisms, including dinosaurs.

5. **Evaluate Option 4**:
- Statement: "Biogeochemical cycles all include both organisms and non-living components."
- Analysis: This statement is true. Biogeochemical cycles involve both biotic (living) and abiotic (non-living) components, as they describe the movement of elements through living organisms and the environment.

6. **Conclusion**: After evaluating all options, the statement that is not true is **Option 1**: "Most elements remain longest in the living portion of their cycle."

### Final Answer:
The statement that is not true about biogeochemical cycles is **Option 1**.

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