Answer:
A nation is a group of people who share some similarities, that can be language, culture, customs, and so on.
A state is a political authority that has territorial control over one specific area. Most states have the monopoly of the use of force.
FInally, sovereignty is the quality that a state has to govern over a specific territory without outside interference.
Mnay states are nation-states, meaning that the same nation also forms a state (for example, Japan), but other states are multinational entities where several nations live together (for example, Russia or India). And sovereignty is a quality that every state possesses, otherwise, they would not have legitimacy over the territory that they hold.
Answer:
The path difference between the two waves should be one-half of a wavelength.
Explanation:
For the destructive interference to form at point P the path difference between the two waves should be
= 
where n can be any integer starting from 0,1,2....
therefore we can say that
If the maximum destructive interference is to occur at point P, The path difference between the two waves should be one-half of a wavelength.
B
Explanation:
Developed in the 20th century as people began to live longer and have fewer children
