From which of the following is quinine obtained?

Which one of the following is most effective in causing the coagulation of an $As_2S_3$ sol?

Match the following components of a cell with their respective percentage of the total cellular mass:

Components	$\%$ of the total cellular mass
$A$. Water	$1$. $10-15$
$B$. Proteins	$2$. $70-90$
$C$. Carbohydrates	$3$. $5-7$
$D$. Lipids	$4$. $3$
$E$. Nucleic acids	$5$. $2$
$F$. Ions	$6$. $1$

The area (in square unit) of the region enclosed by the curves $y=x^2$ and $y=x^3$ is

$A$ clock pendulum made of invar has a period of $0.5 \, s$ at $20^{\circ} C$. If the clock is used in a climate where the temperature averages to $30^{\circ} C$, how much time does the clock lose in each oscillation? (For invar, $\alpha = 9 \times 10^{-7} /{ }^{\circ} C$, $g = \text{constant}$)

$\mathop {\lim }\limits_{x \to 0} \frac{{\sin^2 x}}{{\sqrt{2} - \sqrt{1 + \cos x}}}$ equals