Which term below describes a type of cnida used for food gathering and defense that consist of spines with toxins. 

Match the sponge body type to its description:

An established population begins to have an increased death rate. What is a likely explanation? 

Density-independent factors are factors that influence the number of animals in a population regardless of population size. 

In which of the following cases must price always fall?

Use the following general linear demand relation where M is income and is the price of a related good, R. From this relation it is apparent that the good is

You need gasoline to drive a hybrid vehicle, such as the Toyota Prius. Despite the battery, gasoline is still needed. Based on data, when gasoline prices go up, the demand for hybrid vehicles increases. Based on this data, what can we conclude?

Increases in the wage rates of coal miners and decreases in the price of natural gas (a consumer substitute for coal) would cause the price of coal to

Derrick owns and operates a bakery. Every Saturday he bakes a batch of fresh cinnamon buns, and every Saturday he sells all the cinnamon buns and has to turn some customers away. Which of the following statements is correct?

Moral hazard is a principal-agent problem that arises when