What is the correct order of occurrence ($\%$ by weight) in air of $Ne, Ar$ and $Kr$?

Which of the following reagents is known as Fenton's reagent?

If $a = \cos \left(\frac{8 \pi}{11}\right) + i \sin \left(\frac{8 \pi}{11}\right)$,then $\operatorname{Re}\left(a + a^2 + a^3 + a^4 + a^5\right) = $

If we completely remove the decomposers from an ecosystem,its functioning will be adversely affected because

Which part of the brain is involved in the loss of control when a person drinks alcohol?

In the structure of $B_2H_6$,the number of $BH_2$ groups present in one plane,and the number of $B-H$ terminal bonds,$B-B$ bonds,and $B-H-B$ bridge bonds are respectively: