Circulatory Systems

question 71

Multiple Choice

Circulatory systems

• A) are found in all animals.
• B) result in slow distribution of nutrients and gases.
• C) include one or more hearts.
• D) are always closed systems.
• E) are all of these.

---

Definitions:

Labor

Pertains to the utilization of human labor, encompassing both physical and intellectual efforts, in the creation of products and services.

Marginal Rate

Often referred to in the context of taxes or production, indicating the rate of increase or the additional cost or benefit of producing one more unit of a good.

Technical Substitution

The process of replacing one input or factor of production with another to maintain the same level of output.

Marginal Product

The additional output that results from adding one more unit of a specific input, keeping all other inputs constant.