Answer to Question 1
FALSE
Answer to Question 2
An abstract class is one that cannot have instances, while a concrete class can. If a class has all the required attributes and operations that we expect from an object, then it is concrete. If it has only a subset, then it is abstract and we need a more specialized class. For example Art is an abstract class because we have found it to be too general to satisfactorily represent a specific work of art. Saying that somebody is interested in art does not explain enough. At best, it prompts a question: what kind of art? The answer might be music, literature, painting, theatre, etc. On the other hand, the Literature class has enough attributes to be concrete. That is, we believe it can properly represent an actual literary work.
SpaceShipOne completed the first manned private spaceflight in 2004, reaching an altitude of 100.124
A software inventory log.
Private practice setting.
Four types of covalent modifications that controls that activities of enzymes
Access to clean drinking water is just as important as adequate nutrition for human health
Identifying protein–protein interaction networks