________ Are the Main Primary Producers in Freshwater Environments

question 76

Multiple Choice

________ are the main primary producers in freshwater environments.

• A) Phototrophic microorganisms
• B) Heterotrophic microorganisms
• C) Chemolithotrophic microorganisms
• D) Viral microorganisms

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Definitions:

Composite Unit

A measurement or quantity combining two or more units to represent a product or system's multiple aspects.

Contribution Margin

The difference between the sales revenue and variable costs of a product, indicating how much contributes to covering fixed costs and earning profit.

Contribution Margin

The residual amount from sales income following the deduction of variable expenses, allocated for covering fixed costs and producing profit.

Variable Costs

Expenses that vary in relation to the amount of production or business activity.