the metal ring that covers the holes is called the 'Throat'
the air valve at the base of the burner
It controls the air/gas mixture.
The air inlet is on the burner tube; the flow is regulated with a rotating barrel.
by changing the air flow this can be done by opening or closing the air-hole near the base of the Bunsen burner
This depends on the air flow; it is blue for a complete open air flow.
A Bunsen burner is a device that is used to heat materials in science. It uses a flow of gas and an air hole to regulate the temperature of the flame.
The parts of a Bunsen burner include: the barrel, gas hose, base, collar, air hole and gas flow valve. The Bunsen burner is a small adjustable gas burner that is mainly used in scientific laboratories.
It is called the collar.
The needle valve is used to control the amount of gas flowing to the burner. The air valve controls the amount of air.
A Bunsen burner focuses a lot of heat straight upward, instead of outward. This allows you to heat something up at close range without your hand or anything else getting too hot. Most Bunsen burners have a valve that controls gas flow and adjustable vents where you can control the amount of air that feeds the flame. Bunsen burners are a safe, practical way to apply heat in a chemistry lab.
There are two adjustable parts on the Bunsen burner, the knob to control gas flow and the rotation of the collar to control air flow. The gas flow control, adjusts the size of the flame by controlling how much gas is burned. While the collar controls the intensity of the flame by controlling how completely the gas burns, more complete combustion the hotter the flame. These are the two parts to adjust a Bunsen burner, I hope I have answered your question.
Control of the ratio gas fuel/air in the burner.