The single most important feature to consider when purchasing a scuba regulator is: How well it performs in controlled laboratory testing. A second-stage adjustment knob to ensure ease of breathing. The availability of regular, professional maintenance. Both the first and second answers are correct.

A diving regulator is a pressure regulator that reduces the pressure of gas in the tank and deliver it to the diver so that he/she can breathe easily. It must pass the controlled laboratory testing and must have a second adjustment knob to ensure ease of breathing. Modern regulators are precision made and designed to work under demanding conditions. 1st stage and 2nd stage, diaphragm and piston, exhaust valve and purge button are types of diving regulators.

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.