Polysaccharides have .............. linkage?

Peptidoglycan is present in:

If $\vec{a}, \vec{b}$ and $\vec{c}$ are vectors with magnitudes $2, 3$ and $4$ respectively,then the best upper bound of $|\vec{a}-\vec{b}|^2+|\vec{b}-\vec{c}|^2+|\vec{c}-\vec{a}|^2$ among the given values is

What are the products formed when ammonia reacts with excess chlorine?

For the reaction $FeCO_{3(s)} \to FeO_{(s)} + CO_{2(g)}$,$\Delta H = 82.8 \ kJ$ at $25 \ ^{\circ}C$. What is $\Delta U$ at $25 \ ^{\circ}C$ in $kJ$?

The $DNA$ of $E. coli$ is . . . . . . .