List a few reasons why the oxygen level decreases in case​

Blood oxygen level is the amount of oxygen circulating in the blood. Most of the oxygen is carried by red blood cells, which collect oxygen from the lungs and deliver it to all parts of the body.Blood oxygen level is the amount of oxygen circulating in the blood. Most of the oxygen is carried by red blood cells, which collect oxygen from the lungs and deliver it to all parts of the body.The body closely monitors blood oxygen levels to keep them within a specific range, so that there is enough oxygen for the needs of every cell in the body.Blood oxygen level is the amount of oxygen circulating in the blood. Most of the oxygen is carried by red blood cells, which collect oxygen from the lungs and deliver it to all parts of the body.The body closely monitors blood oxygen levels to keep them within a specific range, so that there is enough oxygen for the needs of every cell in the body.A person’s blood oxygen level is an indicator of how well the body distributes oxygen from the lungs to the cells, and it can be important for people’s health

It’s the energy source of stars