Rickets is a disease of growing bones. Consequently, it usually is seen in young, weaned, growing pigs in which there is a deficiency, an imbalance, or a failure of utilization of calcium, phosphorous or vitamin D. Rickets usually is caused by a dietary deficiency of vitamin D or phosphorus. And Osteoporosis a medical condition in which the bones become brittle and fragile from loss of tissue, typically as a result of hormonal changes, or deficiency of calcium or vitamin D. More than 10 million Americans have osteoporosis, but most do not realize that they have it.
One of the big differences is one occurs mostly to pigs and the other effects adults.Another difference is one occurs while the bones are growing and the other happens after the bones are already grown. I hope this helps!!!
Chemical elements are important to living organisms because they make up the organic molecules that are found in all living things
Reproductive isolation. Species refer to the group of organisms which share common morphological features and can interbreed and produce a viable offspring. Thus, the organisms of one species are reproductively isolated from the organisms of other species
Answer: The correct answer is black because the product of its side and mass is lower.
Explanation: Density of a substance is defined as the mount of matter that can be stored in a given volume.
Mathematically,

As, density is inversely proportional to the volume of the substance.
The substance will be more denser if it has less volume and it will be less denser if the volume is more.
We are given two cubes having different sides.
Volume of the cube is calculated by using the formula:

where, a = side of the cube.
Black: The side of this cube is 2 and volume will be =
Yellow: The side of this cube is 3 and volume will be =
As, the volume of black cube is less. So, this cube will be more denser.
Density of black cube: 
Density of Yellow Cube: 
Hence, black cube will be more denser because the product of its side and mass is lower.