Its the Eccentricity of the earth. (shape of Earth's Orbit around the sun, whether it is more circular or ovular.)
According to the 2011 Earth Science Reference Table, Selenite Gypsum has an approximate hardness of 2.
The hardness of calcite is 3.
The hardness of apatite is 5 according to the Moh's hardness scale.
The hardness of diamond is 10.
no because Separation of oxygenated and deoxygenated blood in the heart of three types of animals. The three-chambered frog heart mixes oxygenated and deoxygenated blood in the ventricle. Therefore, the body never receives fully oxygen-rich blood.