The serpins are components of human plasma and its mutations result in numerous genetic diseases, such as caused by the deficiency of α 1 -antitrypsin. They are proteins of high molecular mass (350-500 amino acids) and have been identified in numerous organisms, from viruses to mammals. The serpins interact with the target enzyme by a similar mechanism on a substrate, although an irreversible interaction where the bond occurs serpin adopts different conformations to interact with the protease target, causing a deformation of the active site of the protease.
The mechanism of inhibition of Trypsin by serpin can be seen in the image below.
Explanation: Well according to the hardness scale the answer would be self explanatory. An example of something at the hardness of 6 is the mineral feldspar which is a pretty solid item, but if you were for example, try to scratch a diamond (a gemstone with a hardness over 6) you would not have any luck scratching anything off that diamond.