Exponential growth rate of a population is graphically represented by -

J-shaped curve

The correct answer is Option (4) → J-shaped curve 

Exponential growth : Exponential growth is a population growth model that describes unregulated, rapid growth where the population size increases continuously without any constraints. The shape of the exponential growth curve is J-shaped, as the population size rapidly increases over time .Resource (food and space) availability is  essential for the unimpeded growth of a population. Ideally, when resources in the habitat are unlimited, each species has the ability to realize fully its innate potential to grow in number.

If in a population of size N, the birth rates (not total number but per capita births) are represented as b and death rates (again, per capita death rates) as d, then the increase or decrease in N during a unit time period t (dN/dt) will be

dN/dt = (b – d) × N

Let (b–d) = r,

then dN/dt = rN

The r in this equation is called the ‘intrinsic rate of natural increase’ and is a very important parameter chosen for assessing impacts of any biotic or abiotic factor on population growth. Population size, technically called population density (designated as N).