Respiration and Gas Transport

In respiration, the human body exhales about 15% of the oxygen that is not utilized by the body. 

Sum of the partial pressure of all gases is 760 mm of Hg.

The amount gases in exhaled air are 4% to 5% by volume more carbon dioxide and 4% to 5% by volume less oxygen than was inhaled. This expired air typically composed of: 78.04% nitrogen; 13.6% - 16% oxygen; 4% - 5.3% carbon dioxide; 1% other gases.

Carbon dioxide can bind to plasma proteins or can enter red blood cells and bind to hemoglobin. This form transports about 10 percent of the carbon dioxide. When carbon dioxide binds to hemoglobin, a molecule called carbaminohemoglobin is formed. Binding of carbon dioxide to hemoglobin is reversible. Therefore, when it reaches the lungs, the carbon dioxide can freely dissociate from the hemoglobin and be expelled from the body. About 30% of CO$ _2$ is transported as carbamino haemoglobin. 

What most people don’t know is that it is, in fact, the level of CO$ _2$ rather than oxygen that usually drives breathing rate. Your body’s ability to detect specific concentrations of CO$ _2$ is extremely sensitive. If the level of CO$ _2$ in your blood increases by a mere 10%, your rate of breathing will double. The answer comes from the way CO$ _2$ is transported. Instead of being bound to hemoglobin, the CO$ _2$ mostly just dissolves in your blood. When the CO$ _2$ dissolves, it combines with the water in your blood to form carbonic acid. As this acid builds up, it dramatically decreases the pH of your blood, throwing it out of balance. Your brainstem detects this pH change, and speeds up your breathing rate in order to to get rid of the extra CO$ _2$. 

Hypoxia, or low oxygen tension in the blood, triggers various physiological responses, including coughing or increased respiratory effort, to improve oxygen intake.

A deficiency of 0xygen always causes a corresponding decrease in the rate of mineral absorption. It is probably due to the unavailability of ATP. The increased oxygen tension helps in increased uptake of salts. So the given statement is false.

The bicarbonate buffering system of blood is an important buffer system in the acid-base homeostasis of living things, including humans. As a buffer, it tends to maintain a relatively constant plasma pH and counteract any force that would alter. In this system, carbon dioxide ${CO _{2}}$ combines with water ${H _{2}O}$ to form carbonic acid ${H _{2}CO _{3}}$, which in turn rapidly dissociates to form hydrogen ions ${H^{+}}$ and bicarbonate ${HCO _{3}^{}}$ as shown in the reactions below.
${CO _{2} + H _{2}O \rightleftarrows H _{2}CO _{3} \rightleftarrows HCO _{3}^{-} + H^{+}}$
The carbon dioxide - carbonic acid equilibrium is catalyzed by the enzyme carbonic anhydrase; the carbonic acid - bicarbonate equilibrium is simple proton dissociation/association and needs no catalyst. Any disturbance of the system will be compensated by a shift in the chemical equilibrium.

Oxygen transport occurs primarily via hemoglobin in RBCs. The small fraction (about 3%) that does not bind to hemoglobin is carried in a dissolved state within the blood plasma.

Homeostasis is the maintenance of a stable internal environment. Blood achieves this by delivering oxygen and nutrients to cells while simultaneously removing metabolic waste products like CO2 and urea.

Globulins, specifically immunoglobulins (antibodies), are essential components of the immune system and are primarily responsible for the body's defense mechanisms.