The matching bolt and nut grades identifying markings are designated differently to demonstrate the strength relationship of the two components. Due to the advent of mass assembly it is an acceptable practice for the matching nut to be the stronger component.
Answers. Best Answer: The altitude and therefore, the temperature, together with the age of the cloud, decides if it is made of ice crystals, water droplets or, both. High clouds only made of ice crystals are called cirrus clouds. Those are the left-overs of strong convection bringing moisture all the way to the tropopause, which is the top of the troposphere. Sometimes, cirrus even escape from the troposphere into the stratosphere.
Cirrus: They are the highest of all clouds and they are composed purely of ice crystals. They occur, specifically, at an altitude of  16,500 to 45,000 feet and they can be found all over the world. Although they are known to form precipitation, none of it reaches the ground.