Answer: simple random sampling
Explanation:
From the question, we are informed that a research team conducts a survey to determine the area of land used for farming in Iowa and that the team randomly selects house addresses and sends the survey by mail.
The type of sampling method which the research team is using market is the simple random sampling method. A simple random sampling is a subset of a larger set whereby all the participants have an equal and fair chance of being selected in the survey participation.