The blood clotting system or coagulation pathway, like the complement system, is a proteolytic cascade. Each enzyme of the pathway is present in the plasma as a zymogen (inactive form), which on activation undergoes proteolytic cleavage to release the active factor from the precursor molecule. The coagulation pathway functions as a series of positive and negative feedback loops which control the activation process.
Spring Yard Zone is the third Zone in the original Sonic the Hedgehog. It is an urban level with many springs and bumpers, resembling a pinball machine. There are many secret areas in this zone. Act 2 has two Robotnik signs (goals) and as such, can be ended through two possible routes.
There are 36 inches in a yard and 12 inches in a foot. The inch is usually the universal unit of measurement in the United States, and is widely used in the United Kingdom, and Canada, despite the introduction of metric to the latter two in the 1960s and 1970s, respectively.