Which of the following conditions is characteristic of logistic growt…

The correct answer is Option (3) → Fixed carrying capacity

A population can grow in two ways. In exponential growth, resources are unlimited and numbers rise without check. In logistic growth, resources are limited, so growth slows and finally stops at the carrying capacity (K), the largest number the habitat can support. The curve is S-shaped (sigmoid).

Option (1) Absence of population resistance — Incorrect. With no resistance, a population would grow without limit. That describes exponential growth, not logistic growth.

Option (2) Abundance of food resources — Incorrect. Plenty of food is the condition for exponential growth. Logistic growth happens because resources are limited.

Option (3) Fixed carrying capacity — Correct. In a habitat with limited resources, growth slows and the population density levels off at the carrying capacity (K). A fixed K is the mark of logistic growth.

Option (4) Growth described by the equation dN/dt = rN — Incorrect. In dN/dt = rN, the growth rate depends only on r and N, with no limit set by K. This is the equation of exponential growth. The logistic equation has the extra term (K − N)/K, which slows growth as N comes near K.

NCERT Extract:
Population Growth – “… (ii) Logistic growth: No population of any species in nature has at its disposal unlimited resources to permit exponential growth. … In nature, a given habitat has enough resources to support a maximum possible number, beyond which no further growth is possible. Let us call this limit as nature’s carrying capacity (K) for that species in that habitat. A population growing in a habitat with limited resources show initially a lag phase, followed by phases of acceleration and deceleration and finally an asymptote, when the population density reaches the carrying capacity.”