The magnifying power of a simple microscope is (when the final image is formed at $D = 25 \ cm$ from the eye):

Which one of the following statements is correct about biodiversity?

The shaded part of the given figure indicates the feasible region. Then the constraints are:

$A$ spherical surface of radius of curvature $R$ separates air (refractive index $1.0$) from glass (refractive index $1.5$). The centre of curvature is in the glass. $A$ point object $P$ placed in air is found to have a real image $Q$ in the glass. The line $PQ$ cuts the surface at the point $O$,and $PO = OQ$. The distance $PO$ is equal to: (in $,R$)

The $Dystrophin$ gene contains how many million bases?

Which of the following exhibits moderate electrical conductivity?