What safety procedure is common to working with both flammable substances and working with glassware?

proper ventilation must be provided.

Explanation:

Glassware and flammable substances must be properly vented when heating to avoid explosion.

Glassware may catch fire if the working area is not properly ventilated.

Flammables substances are those which easily catches fire so in order to avoid any type of explosion it is necessary that these substances are not placed near fire and if it is heating for some reaction there should be proper ventilation.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave

maybe because its impossible for balloons to lift a whole entire house.