The term used to describe how to measure how reflective the surface is, is the surface albedo. Surface albedo represents the ratio of irradiance reflected to the irradiance recieved by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of a solar radiation reaching the Earth's surface.
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In its most general sense, the term "world" refers to the totality of entities, to the whole of reality or to everything that is. The nature of the world has been conceptualized differently in different fields. Some conceptions see the world as unique while others talk of a "plurality of worlds".
The cardiac cycle is defined as the steps involving the conversion of deoxygenated blood to oxygenated blood in the lungs and pumping it by the heart to the body through the aorta. So i think it would be stable over the years unless u have factors that will affect the cycle depending on a persons health