Question

Formation of urine takes place in the following steps

• A. Filtration of blood
• B. Selective absorption
• C. Secretion
• D. All of these

Answer 1

The correct option is D

All of these

The correct option is D.

Explanation of correct option:

The formation of urine takes place in the excretory organ i.e. the kidney's excretory units called nephrons. Nephrons are microscopic cells present in the kidneys. There are millions of nephrons present in the kidneys.

The formation of urine is a process that involves three steps. These steps are as follows:

1. Filtration of blood - Filtration of blood takes place in the region called bowman's capsule by the filtration unit known as the glomerulus. these are small blood vessels that filter all the waste material like salt, water, amino acid, protein, nitrogenous waste, and more. The filtration takes place due to pressure and through its pores.
2. Selective re-absorption - Nephrons have one more region called the tubular region where filtrate enters after filtration. The major part of filtered water, i.e. salts are reabsorbed to make the urine more concentrated.
3. Secretion - The final filtrate is secreted again for some substance after which urine is called by the collecting duct to exit the kidneys.

Thus, the formation of urine takes place through all of these processes; filtration of blood, selective absorption, and secretion.

The formation of urine takes place in the following steps-

1. Filtration of blood
2. Selective absorption
3. Secretion