Mass production facilitates the efficient production of a large number of similar products
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- The latitudinal extent of tropical evergreen forestin the northern and southern hemispheres is 10-degree North and South.
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Answer:
This is a longitudinal research.
Explanation:
Longitudinal research refers to a type of research which takes <em>place over time</em>. It centers on the study of the <em>same variables through time</em> in order to observe the variable's changes.
In this case, psychologist study 5, 7 and 9 year olds and then study them again two years later.
