The two circuits of the cardiovascular system are: Pulmonary Circuit and Systematic Circuit. The pulmonary circuit is shorter than the systemic and is responsible for carrying deoxygenated blood to the lungs from the right atrium, for oxygenation. The systemic circuit is longer and leaves the aortic artery, carrying oxygenated blood throughout the body and nutrients for survival. If less blood were pumped into the systemic circuit, this amount would not be sufficient to compensate for the organism's needs, with the corresponding consequences that this would entail.
It is said that the cardiovascular system is a closed system because blood travels inside a network of blood vessels without leaving them.
An aloe vera plant possessing a trait for extra thick leaves survives very long droughts in deserts, while and aloe vera plant that doesn't have thick leaves doesn't.
Any light that exist was already emitted from somewhere. Any light that is absorbed, is destroyed, and is not emitted light; though, it may lead to light being emitted.
