1. protective sacs (valves ) 2. carries blood to the body (pulmonary)
3. carries blood to the lungs (heart chambers)
4. open and close (pericardium)
5. atria and ventricles (aorta)

Solubility would be your answer.

Electrical charges of ionic bonds

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.