Answer:
The trachea, commonly known as the windpipe, is a most important organ as it allows the passage of air into the lungs. Because the trachea has a soft tissue tubular formation, it needs a base of stronger, yet flexible stuff that will give it support, protect it, and still allow the passage of air into the lungs.
This is precisely the task of the tracheal rings, or cartilage rings in the trachea. These rings are made out of cartilaginous tissue, which is much stronger than the soft tissue of the tubule, but are still flexible enough to not close down the tube when air is flowing in. Thus, the tracheal rings have two tasks: one, provide support and protection for the much softer and more vunerable tube of soft tissue through which the air passes, and two, provide flexibility so that air can flow easily.
If these tracheal rings did not exist, if they are crushed, or removed, a person´s trachea would simply collapse and the person would die as air would not be able to flow through to the lungs.
Answer: Sickle cell disease is caused by a mutation in the hemoglobin-Beta gene found on chromosome 11. Hemoglobin transports oxygen from the lungs to other parts of the body. Red blood cells with normal hemoglobin (hemoglobin-A) are smooth and round and glide through blood vessels.
Explanation:
The correct answer is "a steroid hormone that reduces the amount of fluid excreted in the urine".
Aldosterone is a steroid hormone produced in the adrenal gland, whose main function is the homeostatic regulation of the blood pressure, plasma sodium, and plasma potassium levels.
Aldosterone's main mechanism of action is to regulate the reabsorption of sodium and excretion of potassium in the kidney, which in turn influences the retention of water and the volume and pressure of the blood. Based on all this, aldosterone reduces the amount of fluid excreted in the urine.
