The phase sequential mask is certified for use up tofeet.

The correct answer is "40,000".

Explanation:

According to the Federal Aviation Administration, the phase sequential mask is certified for use up to 40,000 feet, because above this level the pressure will not allow the lungs to take enough oxygen. A specialized system such as pressure demand is necessary in order to fly to higher altitudes. These systems provide oxygen under positive pressure conditions.

it will increase due to the time span

image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.