Answer:
argon and helium
Explanation:
Argon and Helium is belongs to noble gas. Since novel gases are completely filled outer orbital. therefore they are erratic nature. Hence, noble gas are very stable as it neither except electron nor it denote due to it paired of electronic configuration.
Depending on the materials being welded, these atmospheric gases react with welding area and either it reduces the quality of the weld or make the welding more difficult.
Therefore, to protect welding area from atmospheric gases noble gases which are small in size are used.
Thus, argon and helium are used.
\ i believe the word that you are looking for is lava
A good feeling, but i'm not sure what it's called
The main idea of an essay is usually portrayed in the thesis.