Which of the following is not a type of cancer?

Beats are produced by two waves $y_1 = a \sin(1000\pi t)$ and $y_2 = a \sin(998\pi t)$. The number of beats heard per second is:

An object takes $n$ times as much time to slide down a $45^{\circ}$ rough inclined plane as it takes to slide down a perfectly smooth inclined plane of the same inclination. The coefficient of kinetic friction between the object and the rough incline is given by:

Match the following components of a cell with their respective percentage of the total cellular mass:

Components	$\%$ of the total cellular mass
$A$. Water	$1$. $10-15$
$B$. Proteins	$2$. $70-90$
$C$. Carbohydrates	$3$. $5-7$
$D$. Lipids	$4$. $3$
$E$. Nucleic acids	$5$. $2$
$F$. Ions	$6$. $1$

If $a$ and $b$ are positive integers such that $b > a$,then $\lim _{n \rightarrow \infty} \left[ \frac{1}{na} + \frac{1}{na+1} + \frac{1}{na+2} + \ldots + \frac{1}{nb} \right] = $

If a polygon of $n$ sides has $275$ diagonals,then $n$ is equal to