Questions

Glass Box (or white box) testing is the process of giving i/p to the system and checking how the system processes i/p to generate o/p

Black Box testing is the process of giving i/p to the system and checking if the system is giving correct o/p without bothering how the o/p is generated.

As we can see from the definitions, the role of black box testing is to ensure that the o/p generated is correct. And role of white box testing is to ensure that methods used to generate the o/p are correct.

A chemical bond in which the electrons are not shared equally due to differences in the electronegativity of the atoms.

The polarity of a covalent bond is measured using its dipole moment.

 Large dipole moment = more polar

 Small dipole moment = more nonpolar.

No improvement is required. Loan is a temporary provision of money, usage is correct. Debt is an obligation. Demand is a claim to something owed. Advance is a supply in expectation of repayment.

Sound waves cannot be transmitted through vacuum. 

The law of demand implies that "The higher the price of a good, the lesser the quantity demanded".

For example:

If the rate of a mobile phone increased, the quantity demanded by the customers is decreased.

It is any routing protocol used within an autonomous system.

A typedef defines a new name for a type, and in simpler cases like the one shown below you can define a new structure type and a typedef for it at the same time.

typedef struct

{

    char name[20];

    int age;

} emp;

However, in the structure defined in this question, there is an error because a typedef declaration cannot be used until it is defined. In the given code fragment the typedef declaration is not yet defined at he point where the link field is declared.