Which of the following lacks a capsid?

Let $f(x) = \begin{cases} \frac{x^4 - 5x^2 + 4}{|(x - 1)(x - 2)|}, & x \ne 1, 2 \\ 6, & x = 1 \\ 12, & x = 2 \end{cases}$. Then $f(x)$ is continuous on the set

$A$ block of mass $m$ is placed on a surface with a vertical cross-section given by $y = \frac{x^3}{6}$. If the coefficient of friction is $0.5$,the maximum height above the ground at which the block can be placed without slipping is

For the reaction $SnO_{2(s)} + 2H_{2(g)} \rightleftharpoons 2H_2O_{(g)} + Sn_{(l)}$,calculate $K_p$ at $900 \ K$,where the equilibrium steam-hydrogen mixture was $45 \%$ $H_2$ by volume.

If $A = \begin{bmatrix} 0 & 2 \\ 3 & -4 \end{bmatrix}$ and $hA = \begin{bmatrix} 0 & 3a \\ 2b & 24 \end{bmatrix}$,then the values of $h, a, b$ are respectively

The study of the interaction of antigens and antibodies in the blood is known as: