Which process is responsible for the excretion of drugs and toxins from the blood into the filtrate?

Explain the function of collecting tubules.

Which substances are reabsorbed in $PCT$?

Reabsorption of substances according to the needs of the body is called:

Given below are two statements:
Statement $I$: In the nephron,the descending limb of the loop of Henle is impermeable to water and permeable to electrolytes.
Statement $II$: The proximal convoluted tubule is lined by simple columnar brush border epithelium and increases the surface area for reabsorption.
In the light of the above statements,choose the correct answer from the options given below:

The amount of the original filtrate volume which is reabsorbed by the time the tubular fluid enters the Henle's loop is approximately (in $\%$)