The smallest unit of life is...

Observe the following statements:
$I. f(x) = a x^{41} + b x^{-40} \Rightarrow \frac{f^{\prime \prime}(x)}{f(x)} = 1640 x^{-2}$
$II. \frac{d}{d x} \tan ^{-1}\left(\frac{2 x}{1-x^2}\right) = \frac{1}{1+x^2}$
Which of the following is correct?

Which of the following is not a synthetic polymer?

The $K_{\alpha}$ $X$-ray emission line of tungsten occurs at $\lambda = 0.021 \, nm$. The energy difference between $K$ and $L$ levels in this atom is about:

$A$ curve passes through the point $\left(1, \frac{\pi}{6}\right)$. Let the slope of the curve at each point $(x, y)$ be $\frac{y}{x}+\sec \left(\frac{y}{x}\right)$,$x>0$. Then the equation of the curve is

The correct order of dipole moment is