The number of unit cells in $58.5 \ g$ of $NaCl$ is nearly

Which hormone is responsible for apical dominance?

Assume that a drop of liquid evaporates by decrease in its surface energy,so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible? The surface tension is $T$,density of liquid is $\rho$ and $L$ is its latent heat of vaporization.

The angle of elevation of the top of the tower observed from each of the three points $A, B, C$ on the ground,forming a triangle,is the same angle $\alpha$. If $R$ is the circum-radius of the triangle $ABC$,then the height of the tower is

Observe the following statements:
$A$. Integrating factor of $\frac{dy}{dx} + y = x^2$ is $e^x$.
$R$. Integrating factor of $\frac{dy}{dx} + P(x)y = Q(x)$ is $e^{\int P(x) dx}$.
Then,the true statement among the following is:

Arrange $NH_4^+$,$H_2O$,$H_3O^{+}$,$HF$,and $OH^{-}$ in increasing order of acidic nature.