Which one of the following is not used for the construction of ecological pyramids?

The classification of $Monera$ is based on which of the following?

$A$ block of mass $m$ is placed on a surface with a vertical cross-section given by $y = \frac{x^3}{6}$. If the coefficient of friction is $0.5$,the maximum height above the ground at which the block can be placed without slipping is

The value of $\sqrt{(\log_{0.5} 4)^2}$ is

As the mass number $A$ increases,which of the following quantities related to the nucleus does not change?

$A$ parallel plate air capacitor is charged to a potential difference of $V$. After disconnecting the battery,the distance between the plates of the capacitor is increased using an insulating handle. As a result,the potential difference between the plates: