Please choose the correct ending to complete the given sentence: Food and Entertaining: [header] How to make a gas mask [title] Know the difference between gas and particle contamination. [step] Tear gas is actually a dust that is sprayed into the air, whereas biological weapons are generally gases. While it is incredibly difficult and expensive to completely protect yourself against gases, you can easily create a barrier against particles at home.

Ending1: [substeps] You can make a barrier on a piece of cardboard or plastic. Blow up a box box the size and shape of your denser head. Ending2: [substeps] Fuel is often inhaled so that gas vapors are present for a full one minute to erupt. In some situations gas vapor is exposed to the air, which stands to reason should be safe. Ending3: [title] Create a layer that covers the gas as you work in an environment where they do not affect oxygen. [step] Using a fabric thin enough to fit along the sides of the gas tank, you can shield the gas by applying pressure to it at a distant angle. Ending4: [substeps] Toxic ash from volcanoes, tear gas, and dust are all particle contaminates. [title] Cut the bottom off of a transparent 2-liter soda bottle.

Answer format: ending1/ending2/ending3/ending4