This is too general a question. What are you referring to?
Taxonomists use fossil records, morphological structures, and DNA/genetic information in order to classify organisms into different kingdoms, phylums, and classes.
Scientist classify plants as producers due their ability to make their own food. They are in the autotrophic level of the nutrient cycle.
a plant
microscope
Aristotle
Aristotle
mullusks
they look through a microscope
Aristotle
Scientist classify waves by moving through a medium and/or empty space. For example, a wall, air, water, space.
Classifications is first step to differentiation
white and fluffy