Assertion (A) : Physiological density is preferable to arithmetic density as an index of population density. Reason (R) : Physiological density is based on arable land while arithmetic density is based on total area.

Physiological density is considered a superior index of population density compared to arithmetic density because it provides a more accurate reflection of the pressure on a country's resources. Arithmetic density is a simple ratio of total population to total land area, which includes non-habitable or non-productive regions like deserts and mountains [t1][t4]. In contrast, physiological density is calculated by dividing the total population by the net cultivated or arable land area [c1][t5]. This distinction is crucial for countries like India with large agricultural populations, as it reveals the actual human-land ratio and the capacity of the land to support its inhabitants through food production [c3][t3]. Therefore, Assertion (A) is true, and Reason (R) correctly explains why it is preferable by highlighting the specific land base used for the calculation [t2][t9].

Sources

1. [1] INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 1: Population: Distribution, Density, Growth and Composition > Density of Population > p. 5
2. [2] INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 1: Population: Distribution, Density, Growth and Composition > Density of Population > p. 3