The ultimate source of energy for physical life on Earth is the Sun. The answer among the options given above is letter "A. True". The Sun indeed is the source of life on Earth and provides energy for the Earth. I hope this helps.
An open system does not have vessels, but a closed system does.
Explanation:
A closed circulatory system is the one which has blood vessels like arteries, veins, and capillaries for circulation of blood while an open circulatory system is the one in which there are no blood vessels to carry blood and the blood runs freely in the body cavity known as hemocoel. In open circulatory system the tissues are in direct contact with a blood-like fluid known as hemolymph. Evolutionarily, closed circulatory system is considered more advanced and advantageous as compared to open circulatory system. Advanced animals like mammals have closed circulatory system while lower organisms like arthropods (insects) and some mollusks (snails, clams) have open circulatory system.
