Which of the following is a density-independent limiting factor?

D. Tornado.

Explanation:

A limiting factor can be defined as any environmental condition or force (resources) that is capable of affecting the growth rate, distribution and size of a population of living organisms within an ecosystem.

Basically, limiting factors are divided into two (2) main categories and these are;

I. Density-dependent limiting factor.

II. Density-independent limiting factor.

A density-independent limiting factor can be defined as the environmental factors which affect or limit the growth (size) of a population of living organisms irrespective of the population density i.e number of individual organism per unit area.

Some examples of density-independent limiting factors are earthquakes, flood, hurricane, tsunami, wildfire, volcanic eruptions, environmental pollutants, droughts etc.

Hence, a tornado is a density-independent limiting factor because it is abiotic and can kill all the living organisms irrespective of the population density.