Secondary sewage treatment is mainly a

The products obtained in the given reactions are shown below. The number of possible products for $x$ and $y$ is:

What is a phycobiont?

Antrum is a characteristic feature of which follicle?

An electric motor operating on a $60\,V$ $dc$ supply draws a current of $10\,A$. If the efficiency of the motor is $50\%$,the resistance of its winding is....$\Omega$

$\sum_{n=1}^{\infty} \frac{2n^2+n+1}{n!}$ is equal to