Answer: A subcontinent is a large and distinct landmass that is part of a larger continent but is geographically separated from the main continental landmass by geographical features such as mountains, seas, or other natural boundaries. Subcontinents are typically characterized by their unique cultural, geological, and environmental features. The Indian subcontinent, consisting of India, Nepal, Bangladesh, Pakistan, Bhutan, Sri Lanka, and the Maldives.

India classified as a subcontinent:

• Geographical Separation:
• As per plate tectonics, India is a separate plate that collided with the Eurasian plate, leading to the formation of Himalayas.
• India is physically separated from the rest of the Asian continent by natural barriers. The northern border is defined by the massive Himalayan mountain range, which acts as a natural boundary. To the south, India is surrounded by the Indian Ocean. This isolation has contributed to the development of a distinct landmass with unique features.

• Size and physiological diversity: 

• India is one of the largest countries in the world by land area. 
• It has a long land frontier of about 15,200 km and coastline of about 7516.6 km.
• A physiological diversity that can be observed only on continental scale is present in India. For Example, a long coastline, a large desert (Thar), highest mountain ranges, and large plains (India-Ganga-Brahmaputra plains).
• This diversity of geographical features has led to a wide variety of climates, ecosystems, and biodiversity.

• Cultural and Linguistic Diversity: India is home to a rich tapestry of cultures, languages, and traditions. The country's large size has allowed for the development of different regional cultures and languages, making it a salad bowl of diversity.
• India's historical significance, with its ancient roots and birthplace of major religions, along with its economic and political importance as a major global player, makes it a country of immense influence and impact on the world stage.

Implications of large latitudinal and longitudinal extent:

• Climatic diversity: Large latitudinal and longitudinal extents provide diversity in climatic conditions in India. 
• The area south of Tropic of Cancer has a tropical climate as the sun's rays strike the Earth's surface nearly vertically at noon. 
• The oceans on both sides of the peninsular landmass help moderate the temperature through land and sea breezes. 
• Towards the north of the Tropic of Cancer, India experiences a subtropical climate because the Sun's rays strike relatively obliquely. 
• Length of day and night: Regions closer to the equator experience more consistent day and night lengths, while areas farther away from the equator witness more pronounced changes with the seasons, affecting various aspects of daily life and activities.
• Time-zones: The eastern parts receive sunlight much earlier than the western parts, leading to variations in the timings of sunrise and sunset across the country. While a single time zone promotes national unity and coordination, it can also create challenges for people in regions where daylight hours differ significantly from their natural body clocks.
• Biodiversity: Different regions offer unique ecosystems, habitats, and species, contributing to the country's remarkable ecological diversity.
• Resource Diversity: India has immense diversity in terms of availability of resources. 
• Chota Nagpur Plateau is rich in mineral resources. 
• Gangetic Plains are very fertile and contribute greatly to agriculture. 
• Himalayas are gifted with extensive grasslands, forests, and potential mineral deposits. 
• Arid and semi-arid areas are endowed with excellent solar and wind power potential. 
• Cultural and Linguistic Diversity: The large size of India accommodates various cultural traditions, languages, and customs. Different regions have their distinct identities, contributing to the country's cultural tapestry.
• Socio-economic Disparities: The vast expanse of India also gives rise to socio-economic disparities. While some regions prosper economically, others face challenges in development and access to resources.

Therefore, India is a subcontinent in itself with its unique geographical, historical, political and cultural characteristics.