Pyramid of biomass in a marine ecosystem is straight/inverted.

Explanation

### Step-by-Step Solution

1. **Understanding the Pyramid of Biomass**:
- The pyramid of biomass represents the total mass of living organisms at each trophic level in an ecosystem. In a typical ecosystem, biomass decreases as you move up the trophic levels.

2. **Identifying Trophic Levels in a Marine Ecosystem**:
- In a marine ecosystem, the primary producers (like phytoplankton) are at the base, followed by primary consumers (like zooplankton), secondary consumers (small fish), and tertiary consumers (larger fish and sharks).

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