Who was the first scientist to use the term 'virus' as a pathogen of infectious diseases?

Which facilities have made poultry farming a popular business?

$\Delta \lambda$ is the difference between the wavelength of the $K_{\alpha}$ line and the minimum wavelength of the continuous $X$-ray spectrum when the $X$-ray tube is operated at a voltage $V$. If the operating voltage is changed to $V/3$,then the above difference is $\Delta \lambda^{\prime}$. Then:

If the direction ratios $(l, m, n)$ of two lines satisfy the equations $l+m+n=0$ and $mn-2ln+lm=0$,then the angle between the lines is

The correct order of increasing $s-$ character (in percentage) in the hybrid orbitals of the following molecules/ions is:
$I. CO_3^{2-}$
$II. XeF_4$
$III. I_3^{-}$
$IV. NCl_3$
$V. BeCl_2$

Which one of the following is not a micronutrient?