Final answer:
The kidneys are bean-shaped organs located in the abdominal cavity, on either side of the spine, with the right kidney below the liver and the left below the diaphragm and adjacent to the spleen. They are situated retroperitoneally, closer to the back of the body. The correct answer is a. Abdominal cavity.
Step-by-step explanation:
The kidneys are a pair of vital organs responsible for filtering blood, removing wastes, balancing electrolytes, and maintaining fluid balance within the body. In answering where the kidneys are located, they can be found in the abdominal cavity. This cavity includes both the abdominal and pelvic cavities, but it is the former that the kidneys reside in. Each kidney is positioned against the posterior muscle wall of the abdomen and flanks the spine. The right kidney is situated just below the liver, while the left kidney is just below the diaphragm and adjacent to the spleen.
It is important to understand that the kidneys are situated in the retroperitoneal space of the abdominal cavity, high in the back of the abdomen, and are slightly protected by the lower ribs. Despite being part of the abdominal cavity, they are located closer to the back of the body than the front. The right kidney is typically a little lower than the left one due to the presence of the liver, creating a slight asymmetry between their positions.
The anatomy of the kidney itself is complex, with each kidney being divided into an outer renal cortex and an inner renal medulla, which includes the renal pyramids and nephrons, the functional units that filter the blood.
To directly answer the student's question, the correct option is a. Abdominal cavity.