How Did Ptolemy Explain the Retrograde Motion of Mars

question 20

Essay

How did Ptolemy explain the retrograde motion of Mars?

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Definitions:

Lymphatic Vessels

Part of the lymphatic system, these vessels transport lymph, a fluid containing white blood cells and waste products, back into the bloodstream.

Valves

Structures that open and close to control the flow of fluids in one direction, commonly found in the heart and veins of the circulatory system.

Vaccinations

The administration of antigenic material (a vaccine) to stimulate an individual's immune system to develop adaptive immunity to a pathogen.

MHC Class I

Molecules found on the surface of all nucleated cells that present peptide fragments to the immune system, crucial for the recognition of self-cells by T cells.