Which of the following processes forms somatic cells?

A. Myelin is a fatty substance that wraps around axons in many neurons. It acts as an insulative covering that speeds up the transmission of nerve impulses by enabling the signal to jump between gaps in the myelin (called nodes of Ranvier). This is the correct answer.

B. The synapse is the junction between two neurons where signals are transmitted. It is not involved in the insulative covering of a neuron.

C. The axon is the long, slender part of a neuron that transmits electrical signals, but it requires myelin to efficiently conduct those signals.

D. Dendrites are branched extensions of a neuron that receive signals from other neurons. They do not have an insulative function.

A. Bowman's capsule is the site of initial filtration in the kidney, where blood plasma is filtered into the nephron. However, it does not participate in the reabsorption of water.

B. The proximal convoluted tubules are where the majority of water, along with glucose, amino acids, and ions, is reabsorbed. This segment is crucial for maintaining fluid balance in the body.

C. The renal pelvis is a funnel-like structure that collects urine from the collecting ducts and channels it into the ureter for excretion. It does not play a role in reabsorption.

D. The ascending loop of Henle is primarily involved in the reabsorption of salts (sodium and chloride), but not water, as it is impermeable to water. Water reabsorption occurs in other parts of the nephron, such as the proximal convoluted tubule and the descending loop of Henle.