1. The average life of red blood cells in the human body is 120 days. This is the time it takes from the formation of red blood cells until they flow in the blood. Red blood cells are made in the bone marrow and then they are shed into the blood. While flowing in the blood, red blood cells carry oxygen from the lungs to the rest of the body and carry carbon dioxide from the rest of the body to the lungs.

lactic acid is one of the end products of anaerobic respiration in humans and some other organisms. During anaerobic respiration, which occurs in the absence of oxygen, glucose is partially broken down to generate energy. In the absence of oxygen, cells can convert pyruvate, a product of glycolysis, into lactic acid. This process, called lactic acid fermentation, helps generate energy in the absence of oxygen but also leads to the accumulation of lactic acid, causing muscle fatigue and soreness.

1. Involuntary actions like blood pressure, salivation and vomiting are controlled by the medulla.

2. The medulla oblongata, also called the medulla, is the lowest part of the brain and the lowest part of the brainstem.

3. The medulla oblongata or simply the medulla is a long stem-like structure that is part of the brain.