Choose the correct option:
$(1)$ $ANF$ is secreted when blood pressure decreases / blood pressure increases.
$(2)$ Renal pyramids are located in the renal cortex / renal medulla.

Which one of the following correctly explains the function of a specific part of a human nephron?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Nephrons are of two types: Cortical and Juxta-medullary,based on their relative position in the cortex and medulla.
Reason $R$: Juxta-medullary nephrons have a short loop of Henle,whereas cortical nephrons have a longer loop of Henle.
In the light of the above statements,choose the correct answer from the options given below:

The duct of Bellini opens into the ........ .

The vessel leading blood (containing nitrogenous waste) into the Bowman's capsule is known as:

Draw a neat and labelled diagram of an excretory unit (nephron).