When ethene reacts with bromine,it forms

The major product in the reaction is

What will be the major product of each of the two reactions shown below?
$1.$ $CH_3-CH_2-CH(N^{+}(CH_3)_3)OH^{-} \xrightarrow{\text{heat}} CH_3-CH=CH-CH_3 (X) + CH_3-CH_2-CH=CH_2 (Y)$
$2.$ $CH_3-CH_2-CH(Br)-CH_3 \xrightarrow{\text{heat}} CH_3-CH=CH-CH_3 (X) + CH_3-CH_2-CH=CH_2 (Y)$

What is the major product of the following reaction?
$3$-methylenecyclohexan-$1$-ol + $H_2$ ($1$ eq.) / $Ni$,$\Delta$ $\rightarrow$ ?

For the reaction: $CH_2=CH-CH=CH_2 + HBr (1 \text{ eq}) \xrightarrow{80^{\circ}C} P_1 + P_2$ (where $P_1$ is the major product),identify $P_1$.

Provide information about the structure and isomerism of alkenes.