Hmmm

ii)Transition metals and their compounds show catalytic activities because of Variable or multiple oxidation states, ability to form complexes, they provide large surface area for adsorption.

The answer is A 

In the depletion layer, electrons combine with holes producing charge density so that region is depleted of charge carriers  but it has charge density .

Conclusion: Neutral but still having non zero charge density .

Aksionov used to drink a lot, was riotous, and was involved in illegal activities before his marriage

Balance on a bicycle is a matter of constantly correcting against falls, and it's easier when the speed is higher because the inertia of moving forward overcomes the need for corrective actions.