Core Legal Answer & Context: Nationality is the legal bond between an individual and a state, conferring rights and duties. States have the sovereign right to determine who their nationals are through their domestic laws.

Modes of Acquisition of Nationality:

1. Jus Sanguinis (Right of Blood): Nationality is acquired through parentage, regardless of the place of birth. If one or both parents are nationals, the child acquires that nationality (e.g., India, Germany).
2. Jus Soli (Right of Soil): Nationality is acquired by birth within the territory of a state, regardless of the nationality of the parents (e.g., USA, Canada).
3. Naturalization: A process by which a foreign national voluntarily acquires the nationality of another state after fulfilling certain conditions (e.g., period of residence, language proficiency, good character, oath of allegiance).
4. Registration: A simplified form of naturalization, often available to spouses of nationals, persons of Indian origin, or minors.
5. Incorporation of Territory: When a territory becomes part of a state, the inhabitants of that territory may automatically acquire the nationality of the incorporating state.

Modes of Loss of Nationality:

1. Renunciation: Voluntary relinquishment of nationality by a person who holds dual nationality, usually by making a formal declaration.
2. Termination/Deprivation: Involuntary loss of nationality by state action, often due to disloyalty, fraud in obtaining nationality, serving in a foreign army, or prolonged residence abroad without intent to return.
3. Expatriation: Voluntary departure from one's home country to reside permanently in another, which in some jurisdictions can lead to the loss of original nationality.
4. Substitution: Acquisition of a new nationality, which automatically leads to the loss of the previous one in states that do not permit dual nationality.

Relevant Statutes and Sections:

1. The Citizenship Act, 1955 (India): Governs the acquisition (by birth, descent, registration, naturalization, incorporation of territory) and loss (by renunciation, termination, deprivation) of Indian citizenship.

Important Landmark Cases:

1. Nottebohm Case (Liechtenstein v. Guatemala, ICJ, 1955): While not directly on modes of acquisition, it established the principle of a 'genuine link' between an individual and a state for nationality to be opposable against other states, particularly in cases of naturalization, emphasizing the real connection required.

Clear Conclusion: States determine their own nationality laws, typically employing a combination of jus sanguinis and jus soli for birthright citizenship, alongside naturalization for foreign nationals. Loss of nationality can be voluntary (renunciation) or involuntary (deprivation), reflecting the state's sovereign right to regulate its citizenry and the individual's choices.