The Symbols +, -, and 0 Are Used to Show

question 17

Multiple Choice

The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. Which fact is correct when describing species interactions?

• A) +/0 will always remain such.
• B) A +/- interaction could shift to +/0 or +/+ over time, depending on other factors such as competition, population density, or environmental changes.
• C) Species interactions occur in isolation and cannot affect the structure of ecological communities.
• D) A -/- interaction benefits both of the species in the relationship.

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Definitions:

Variable Cost

Outlays that adjust in accordance with the volume of production or output, like materials and labor costs.

Loan

A sum of money that is borrowed and expected to be paid back with interest.

Economies of Scale

Refers to the cost advantage that arises with increased output of a product, leading to a reduction in the per-unit cost.

Marginal Cost

An alternative phrasing expressing the additional cost incurred from the production of the next unit of output.