What is common among silverfish,scorpion,crab,and honeybee?

If an electron and a proton have the same de-Broglie wavelength,then the kinetic energy of the electron is

Genes that are involved in turning on or off the transcription of a set of structural genes are called

What are $X$ and $Y$ in the following reaction?
$CF_2Cl_2 \xrightarrow{UV} X + Y$

If the length of the tangent from $(h, k)$ to the circle $x^2+y^2=16$ is twice the length of the tangent from the same point to the circle $x^2+y^2+2x+2y=0$,then

Which of the following orders are correct?
$I$. Thermal stability : $BeSO_4 < MgSO_4 < CaSO_4 < SrSO_4 < BaSO_4$
$II$. Basic nature : $ZnO > BeO > MgO > CaO$
$III$. Solubility in water : $LiOH > NaOH > KOH > RbOH > CsOH$
$IV$. Melting point : $NaCl > KCl > RbCl > CsCl > LiCl$