What is the function of an arthropod's hardened exoskeleton?

The exoskeleton will have thickened areas in which the chitin is reinforced or stiffened by materials such as minerals or hardened proteins.

The truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey