Before the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) was created and implemented, there were many different regulations on hazard classification in use in different countries, resulting in multiple standards, classifications and labels for the same hazard.
Pneumatics Vs Hydraulics. The pros and cons of each system. Pneumatics offer a very clean system, suitable for food manufacturing processes and other processes which require no risk of contamination. Hydraulics is generally not used in these environments due to the risk of hydraulic oil leaks from faulty valves, seals or burst hoses.
Circulatory Systems. Another difference between annelids and arthropods is their circulatory system. Annelids and humans have closed circulatory systems in which the heart pumps blood into vessels. The blood is always contained in the vessels -- it does not enter the rest of the body.