An intervening variable facilitates a better understanding of the relationship between the independent and dependent variables when the variables appear to not have a definite connection. They are studied by means of operational definitions and have no existence apart.
Difference between Microevolution and Macroevolution. â¢ Micro evolution refers to visible changes in a population of the same species over a period of time. â¢ Macroevolution is what evolution is as described by the theory of evolution by Darwin.
A somewhat more invasive procedure is a core needle biopsy. The difference between the 2 procedures is that the core needle biopsy takes actual pieces of solid tissue, whereas the fine needle aspiration biopsy takes just a few cells, which are then examined under the microscope.