Explain how using an open circulatory system constrains the size of animals.

An open circulatory system constrain animals size because there is no motor that pump the hemolymph (hemolymph is like the blood in invertebrate animals), in a closed circulatory system is the heart that works as a motor to move the blood throught all over the body.

So the hemolymph can not travel through long distances what constrain the size of the animals that have open circulatory system.

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.

its temperature is increasing. this causes molecular vibrations to increase.