en dealing with constructors, destructors, and mem ms, which access specifier should be used? To what purpose

*Initial Class Diagram is attached below Refine the UML class diagram so that it demonstrates the following: Classes (using the complex class symbols), Associations (with multiplicities AND association names), Generalizations (if any), and Compositions (if any) Focus ONLY on the following activities within the system: Start a Trip, Reserve a Vehicle, Make a Parking Reservation, Make a Charging Session for a Personal Vehicle, End a Trip or Charging Session, and Submit a Support Ticket for a Vehicle or Station Add the primary key necessary to support any relationships that have a multiplicity of "1" as an attribute in the corresponding class

It is necessary for a subclass of an abstract class to implement all of the abstract methods that are defined for the parent class. Is there a mistake or is it accurate?

A subclass of an abstract class must provide concrete implementations for each of the parent class's abstract methods in order to be considered a subclass. What are your thoughts on this?