The oxy/acetylene welding torch is used to ___ the oxygen and acetylene gases in the proper proportioned, and to control the ____ of these gases burned at the tip.

The correct answer emphasizes the function of the oxy/acetylene welding torch, which is to mix gases in a precise manner and control the volume of these gases being burned at the torch tip.

In the context of oxy/acetylene torches, mixing oxygen and acetylene in the correct proportions is crucial for achieving efficient combustion, producing a flame that is optimal for welding, cutting, or brazing operations. The quality of the flame and the heat generated depend heavily on how well the gases are mixed.

Furthermore, controlling the volume of gases at the tip allows the welder to adjust the flame size and temperature based on specific welding needs or material characteristics. Adequate volume control ensures that the right amount of gas is used, thereby maintaining the necessary heat output without wastage.

The use of "mix" rather than "blend" in this case highlights the intentional process of combining the two gases to achieve a desired ratio, which is fundamental to effective welding operations.