Question

What do you mean by intensive subsistence agriculture?

Answer 1

Hint: This form of agriculture is best grown in and almost exclusive to Asian monsoon lands.
The farming is so intense that double or triple crops, that is, multiple crops are cultivated on the same soil over the course of one year. Where one single crop of paddy can be grown, other food or cash crops such as sugar, tobacco and oil-seeds are usually used during a dry season.

Complete answer:
Intensive subsistence agriculture means a form of agriculture characterised by high production per unit of land and relatively low output per worker. While the essence of this farming has changed and it is no longer subsistence in many areas now.
But the word 'intensive subsistence' is still used today, despite changes, to describe certain agricultural systems that are obviously more advanced than primitive agriculture. It is often referred to as 'agriculture of the monsoon type.'
Farming needs to be very intensive in the wetlands and in the terraced mountains, to sustain a dense population. In some agricultural regions, population densities in Asia are higher than in western industrial areas. Many of the intensive subsistence-based agriculture regions have a highly-developed social and governmental nature and some of them have a continuous civilization background dating back over four thousand years.

Note: Intensive farming characteristics:-
The increase of output is by using high yield varieties (HYVs), modern chemical input and irrigation.
The production is very high per hectare.
During one year more than one crop is grown.