which study is a researcher who wants to draw correct cause-and-effect conclusions about the sense of smell likely to conduct?

What does the term "deforestation" mean? what landform are we studying that deforestation is impacting greatly in brazil? describe how and why this is happening. plz me!

In a citizens elect the president as head of government separate loy from the legislature

Why are the majority of the world's economies mixed? what may happen to the "pure" types of economies (traditional, socialist/command, market capitalist) when they incorporate elements from other economic models?