Unlike ionic bonds, covalent bonds involve the a. gain of one or more electrons by one atom from another. b. loss of one or more electrons from one atom to another. c. development of positively and negatively charged ions. d. sharing of electrons between atoms.

Ionic bonds are when atoms gain or lose electrons, giving it a charge (positive or negative), A covalent bond shares electrons and gets a neutral charge. 

Therefore, our answer is D.

Final - D. sharing of electrons between atoms.

Calcinosis is the diagnostic term that means an abnormal buildup of calcium on the kneecap (patellar) surface. it is a term uses to describe a group of disorders in which calcium deposits form in the skin. it is also referred to the abnormal deposit of calcium phosphate.