Which is a density-dependent factor?

Question

Cohort, dispersion, allee effect, iteroparous, semelparous

Answer 1

Density dependent factors are biotic factors (biological) and involve things like competition,feeding, mating etc.

All the ones on your list are biotic and therefore density dependent.

Cohort -a group of individuals.

Dispersion - to do with area/sapace and numbers.

Allele effect - genetics - depends on mating etc.

Iteroparous -  breeding mechanism - multiple times.

Semelparous - breeding mechanism = once per lifetime.

Answer 2

The Allee effect is, by definition, density-dependent.  It describes how when population density decreases, reproductive output decreases at a disproportionally higher rate.