How do the different layers of e protocol hierarchy interact with each other? Why do we need to have two different layers that work on error detection and correction?

Mary's manager told her she should insert a graphic into her documentwrite mary a brief note describing how to insert a graphicin a word processing document.

1)consider the following code snippet: #ifndef book_h#define book_hconst double max_cost = 1000.0; class book{public: book(); book(double new_cost); void set_cost(double new_cost); double get_cost() const; private: double cost; }; double calculate_terms(book bk); #endifwhich of the following is correct? a)the header file is correct as given.b)the definition of max_cost should be removed since header files should not contain constants.c)the definition of book should be removed since header files should not contain class definitions.d)the body of the calculate_terms function should be added to the header file.

So im doing this school challenge and the teachers said whats the average text a student gets a day so i need to get about 20 in a day but dont know how can you guys 2163371293