Which of the following regulates blood pressure and heart rate?

$A$ $0.001 \, \text{molal}$ solution of $[Pt(NH_3)_4Cl_4]$ in water shows a freezing point depression of $0.0054 \, ^circ C$. If $K_f$ for water is $1.80$,the correct formulation of the above compound is?

Which of the following elements has the least number of electrons in its $M$ shell?

The differential equation of the family of parabolas with vertex at $(0, -1)$ and having axis along the $Y$-axis is

$A$ polaroid is placed at $45^{\circ}$ to an incoming linearly polarized light of intensity $I_0$. The intensity of light passing through the polaroid after polarization would be:

From which of the following can a milk-like substance be prepared?