The periosteum is attached to the main bone due to this structure is . articular cartilage
. diaphysis
. sharpeys fibers
. arteries

The basic repeating unit of nucleic acids are known as nucleotides. a nucleotide consists of three distinct chemical groups.

Iguess i would say diagrams would be most difficult subject too correct

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on