2011 â The first of its kind in North America, EdgeWalk is the worldâs highest full circle hands-free walk on a 5 ft (1.5 m) wide ledge encircling the top of the CN Towerâs main pod, 356m, (1168 ft, 116 stories) above the ground.
Why does cellular respiration add carbon dioxide to the atmosphere but photosynthesis does not? During photosynthesis, carbon dioxide and water are used to produce sugars and oxygen. During respiration, the sugar glucose and oxygen and used to produce carbon dioxide and â¦water.  Resource: Science Explorer. Prentice Hall Life Science Text Book. No copyright intended.
However, the revised IDLH for chromium metal is 250 mg Cr/m3 based on being 500 times the NIOSH REL of 0.5 mg Cr/m3 (500 is an assigned protection factor for respirators and was used arbitrarily during the Standards Completion Program for deciding when the most protective respirators should be used for particulates).