Answer: Modularity was introduced to support construction of
large programs. A module is a large program units that can be 
implemented as an independent entity. A well-designed module 
typically has a single purpose and represents a narrow interface 
to other modules. A module typically makes only a few components
visible outside. Such components are said to be exported by the 
module. Other modules remain hidden inside the module and used 
for implementing the visible components. Modules are designed to 
be resuable. 

Solution:

Yes, agree with the statement. Use of abstraction allows us to
concentrate on general ideas rather than on specific 
manifestations of these ideas. In programming, abstraction
refers to what a piece of code does rather that how it is
implemented. For example, in C/C++ consider the difference 
between a .h file (prototype declaration-what the program 
does)and a .c file (how the program does it, i.e., its 
implementation).

3. Give an example of a parameterless abstraction (i.e. a procedure, or a function which has no parameters) that does not perform exactly the same computation every time it is called. Under what circumstances, in general, will a parameterless abstraction behave like this?

Solution:

  int a;  // global variable a

  void test() {
    cout << 2*a;
  }
  ...
  int main() {
    a = 2;
    test();
    a = 3;
    test();
    ...
  }
In general, a parameterless abstraction may not perform exactly 
the same computation every time it is called if it relies on the 
exterior environment for at least one of the values that it uses.