The position of kidneys is
A. Intraperitoneal
B. Retroperitoneal
C. Intraperitoneal
D. None of these

Hint: Nephrons are the structural and functional units of the kidney that are present in kidneys. About 1 million nephrons are present in each human kidney. It controls the volume of various body fluids, maintains osmolality and acid-base balance. It is present below the diaphragm.

Complete answer: Two bean-shaped organs found in vertebrates are called kidneys. They are located on the left and right in the retroperitoneal space, and in adults, they are about 12 centimetres in length. The kidneys receive blood from the paired renal arteries and exits into the renal veins that are present in pairs. Each kidney is attached to the tube that carries excreted urine to the bladder called the ureter. The glomerulus is a part where the filtration occurs. The amount of blood filtered in the kidneys is one-fifth. Solute-free water, amino acids, glucose, and sodium bicarbonate are common examples of substances that are filtered, whereas substances like ammonium, potassium, hydrogen, and uric acid are secreted from the kidneys. The right kidney is posterior to the liver and is present below the diaphragm. Whereas, the left kidney is present in a vice-versa manner. The adrenal gland is present on the top of each kidney. 11th and 12th ribs protect the upper part of the kidneys, where each kidney is surrounded by two layers of fat with its adrenal gland at the top. Between renal fascia and renal capsule, the perineal fat is present, and superior to the renal fascia parental fat is present.
Hence, the correct answer is option B.

Note: In the abdominal cavity, kidneys are located; one on either side of the spine that lies at the slightly opposite angle. Due to the liver position, the kidney gets the asymmetry part in it that typically results in the right kidney being slightly lower and smaller than the left and being placed slightly more to the middle than the left kidney.