A Student Observes a Worm-Like Organism Crawling About on Dead

question 96

Multiple Choice

A student observes a worm-like organism crawling about on dead organic matter. Later, the organism sheds its outer covering. One possibility is that the organism is a larval insect (like a maggot) . On the other hand, it might be a member of which phylum, and one way to distinguish between the two possibilities is by looking for the presence of

• A)Platyhelminthes; a cuticle of chitin.
• B)Nematoda; an alimentary canal.
• C)Annelida; a body cavity.
• D)Nematoda; a circulatory system.
• E)Annelida; muscle in the body wall.

---

Definitions:

Economic Profits

The excess of total revenues over total costs, including both explicit and implicit costs, indicating a return above the firm's opportunity costs.

Average Rate

The mean value of a set of rates or percentages, calculated as the sum of all rates divided by the number of rates.

Above Average Profits

Earnings that surpass the norm or average level within a particular industry or market.

Perfectly Elastic Demand

A market situation where demand for a product can drastically change to infinity with the slightest change in its price.