Jon likes hiking. he observes that whenever he hikes up a hill, he breathes heavier than when he is on flat ground. which two statements explain why this happens? sensors in the brain detect a lack of oxygen. the muscles in his body need more energy and therefore more oxygen. the body has too little carbon dioxide to maintain function. the body is using carbon dioxide instead of oxygen to make energy. blood pressure has decreased, so less blood is being pumped to the muscles.

The correct statements are:

The amount of oxygen in air and atmospheric pressure decreases with increase in altitude.

So, when Jon hikes up the hill he faces two problems; lack of oxygen in the air and decrease in atmospheric pressure.

Decreased atmospheric pressure makes it difficult for the lungs to breathe in the air and lack of oxygen decrease the blood oxygen level.

In addition, physical activity like hiking increases the oxygen demand of the body.

Due to these factors the respiratory system struggles to meet the oxygen demand of the body. The brain detect the same and triggers the respiratory and circulatory system to work more in order to meet the oxygen demand.

It causes the shortness of breath or heavy breathing, high blood pressure, tiredness, dizziness etc.

The correct statements are:

Sensors in the brain detect a lack of oxygen.

The muscles in his body need more energy and therefore more oxygen.

Explanation:

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate