What is an interaction? describe an example and identify the variables within your population (work, social, academic, etc.) for which you might expect interactions?

An interaction is the action that occurs in 2 people while having any kind of conversation.For example ,I am interacting with you by telling an answer. A population interaction example is, a dog and a flea.The flea jumps in the dog and drinks its blood.The dog scratches itself.This is an example of parasitism where one is benefited and other is harmed.

even though you have attached neither the chart nor the generalizations, i have located them online. the right answer is d, since they are asking you about a generalization. you can only infer from the chart that between 2008 and 2009 the number of employed workers decreased significantly (from over 115 millions to 107 millions approximately), which signals some type of economic crisis.  

propioception;