A shared derived characteristics is usually a homologous structure, such as a backbone, that is shared by all organisms in a group.
We cannot see it its so small
Also yes it matches your hypothesis
a strong acid fully dissociates in water to form H+ ions in water while a weak acid only partially dissociates to form H+ ions in water
CH_3 CH_2 Cl has two different types of hydrogen. On further chlorination they are being substituted by chlorine to give two isomeric dichlorides
The structures of the two chlorides are shown below.
Where Hb is replaced by Cl and Ha is replaced by Cl