Which of the following companies started selling Humulin in $1983$?

Which of the following has the most acidic proton?

$A$ closed pipe is suddenly opened and changed to an open pipe of the same length. The fundamental frequency of the resulting open pipe is less than that of the $3^{rd}$ harmonic of the earlier closed pipe by $55 ~Hz$. Then,the value of the fundamental frequency of the closed pipe is: (in $~Hz$)

Which of the following pairs of substances illustrates the law of multiple proportions?

The area bounded by the curves $y = x(x - 3)^2$ and $y = x$ is (in sq. units) :

What is the period of small oscillations of the block of mass $m$ if the springs are ideal and pulleys are massless?