Which of the following is an acidic salt?

One end of a uniform glass capillary tube of radius $r=0.025 \ cm$ is immersed vertically in water to a depth $h=1 \ cm$. The excess pressure in $N/m^2$ required to blow an air bubble out of the tube is: (Surface tension of water $T=7 \times 10^{-2} \ N/m$,Density of water $\rho=10^3 \ kg/m^3$,Acceleration due to gravity $g=10 \ m/s^2$)

Pheromone is

Which one of the following is a slime mould?

In how many ways can $8$ identical balls be distributed into $3$ distinct boxes such that no box remains empty?

The radius of germanium $(Ge)$ nuclide is measured to be twice the radius of ${}_4^9Be$. The number of nucleons in $Ge$ are