From which of the following minerals is $Ra$ (Radium) obtained?

Among $Ni(CO)_4$,$[Ni(CN)_4]^{2-}$,and $[Ni(Cl)_4]^{2-}$,which of the following statements is correct regarding their magnetic properties?

To increase milk yield,a cow is given:

Which logic gate is represented by the following combination of logic gates?

Identify the incorrect pair for Gymnosperms from the following:

When a plane mirror is rotated through an angle $\theta$,the reflected ray turns through an angle $2\theta$. What happens to the size of the image?