The essential chemical components of many coenzymes are

If $\bar{a}$ and $\bar{b}$ are two unit vectors such that $\bar{a}+2 \bar{b}$ and $5 \bar{a}-4 \bar{b}$ are perpendicular to each other,then the angle between $\bar{a}$ and $\bar{b}$ is

The length of the latus rectum of the parabola $y^2+8x-2y+17=0$ is

The equations $x-y=4$ and $x^2+4xy+y^2=0$ represent the sides of a/an

Which of the following is the correct group for the three-domain system of classification proposed by Carl Woese?

The bond energy of $Cl_2$,$Br_2$,and $I_2$ follows the order: