First Aid

2 seconds

You should maintain pressure on the casualty's chest for 2 seconds during artificial respiration. This duration is followed by a 3-second relaxation period in the kneeling position. 1 second (option A) is too brief to create effective pressure on the diaphragm. 3 seconds (option C) is the relaxation time, not pressure time. 5 seconds (option D) is too long and could cause injury.

Covering open wounds to reduce bleeding and prevent infection

Sterilized gauze rolls are primarily used to cover open wounds to reduce bleeding and prevent infection. They come in various sizes (2"x2", 3"x5", 5"x9") to accommodate different wound sizes. Joint support (option A) is the function of elastic crepe bandages. Cleaning equipment (option B) is not their primary medical use. Measuring wounds (option D) is not their intended purpose.

Face down with head turned to one side

The casualty should be placed face down with the head turned to one side. This position allows water to drain from the mouth and prevents choking. Face up (option A) could cause the person to choke on water or vomit. Face down with head straight (option C) doesn't allow proper drainage. Sideways position (option D) is not the recommended position for this specific technique.

Metal or similar clips

Elastic crepe bandages are secured in place with metal or similar clips. These clips are specifically designed to hold the elastic material firmly without slipping. Adhesive tape (option A) is not typically used with crepe bandages as it can reduce their elasticity. Safety pins (option C) could puncture the elastic material. String ties (option D) are not secure enough for the stretchy material.