Answer to Question 1
D
Answer to Question 2
Classes and objects are black boxes: their outside is visible while their inside is not. This characteristic is achieved through encapsulation, the enclosing of data and processes within one single unit. Information hiding, which follows encapsulation, ensures that the inner entities and the workings of the object are concealed (and safe) from outside entities.
Encapsulation results in two spaces: public (the outside) and private (the inside). What the object offers to the public is called its interface. The interface is both the services that an object provides and the form that these services take. Since, in an information system, the only reason for an object's existence is the services that it offers to other entities, the interface of the object is characterized as a contract or a binding agreement.
Under this contract, an object assumes certain responsibilities. The responsibilities fall into two categories: what the object knows, or attributes, and what the object does, or operations. A class defines the responsibilities and its instances (the objects) carry them out.
Even though an object is a building block of an information system, it might be composed of other objects. Such objects are called composite objects. A collection object is a composite object that is made up of objects instantiated from the same class. Composite objects may belong to a hierarchy: a component of a composite object may itself be a composite object.
The actions of Frzb and the Frizzled receptor protein show how embryonic development represents a ba
Kohlberg's Stages of Moral Development
Cognitive Development of Children (2 of 4)
Limb growth development of Salamander Experiment
Human Development (Full Term)
Stages of development in vertebrates.