Spider Crabs Live on the Ocean Floor in Shallow Areas

question 65

Multiple Choice

Spider crabs live on the ocean floor in shallow areas and greenish-brown algae live on their backs. This provides the algae with a home and the algae's greenish-brown color helps the crab blend in and stay safe from predators. This association can be considered a mutualism because

• A) both partners receive a net benefit.
• B) the association is an altruistic one.
• C) one partner benefits and the other is not harmed.
• D) the crab obtains a greater net benefit than the algae.

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Definitions:

Average Cost

The total cost divided by the number of units produced, indicating the cost per unit of output.

Marginal Cost

The increase in total cost that arises from an extra unit of production, pivotal for decision-making in production processes.

Diminishing Returns

A principle stating that as more of a variable input is combined with a fixed input, the incremental gains in output will eventually decrease.

Increasing Returns

This refers to a scenario in economics where, as the quantity of input increases, the rate of output increases at a faster rate, leading to economies of scale.