Which of the following is $NOT$ a part of the intratesticular genital duct system?

Which of the following is a cationic detergent?

The current in the windings of a toroid is $2.0\,A$. There are $400$ turns and the mean circumferential length is $40\,cm$. If the magnetic field inside the toroid is $1.0\,T$,the relative permeability is near to:

Suppose that a random variable $X$ follows a Poisson distribution. If $P(X=1) = P(X=2)$,then $P(X=5)$ is equal to:

$\lim _{x \rightarrow \infty} \left(\frac{x+a}{x+b}\right)^{x}$ is equal to

The oxidation state and covalency of $Al$ in $[AlCl(H_2O)_5]^{2+}$ are respectively