If ${}^n{P_4} : {}^n{P_5} = 1 : 2$,then $n = $

Stimulation of a muscle fiber by a motor neuron occurs at:

The coefficient of static friction,$\mu_s$ between block $A$ of mass $2\,kg$ and the table as shown in the figure is $0.2$. What would be the maximum mass value of block $B$ so that the two blocks do not move (in $,kg$)? The string and the pulley are assumed to be smooth and massless. $(g = 10\,m/s^2)$

The foot of the perpendicular from $(0,2,3)$ to the line $\frac{x+3}{5}=\frac{y-1}{2}=\frac{z+4}{3}$ is

The perpendicular distance of the straight line $12x + 5y = 7$ from the origin is given by

What is the foundation of any breeding program?