What is used as snuff?

Heroin is chemically known as $......$.

The liver of an alcoholic person gets damaged because...

Liver cirrhosis is caused by ...........

Assertion: Heroin,commonly called smack,is chemically diacetylmorphine.
Reason: This is obtained from the acetylation of morphine.

Nicotine intake stimulates the $...A...$ to release $...B...$ and $...C...$ into blood circulation. This leads to an increase in $...D...$ and an increase in $...E...$. Here $A$ and $E$ refer to: