The correct answer is predation and disease.
Density dependent factors are those factors, which are directly influenced by the density of a population. These factors directly influence the size and the growth of the population.
The predation and the disease are density dependent factors, as predation of a small density population would cause a significant decrease in number, so, predation is the limiting factor for the growth of the population. Same for diseases, the disease can affect most of the members of the population, and limiting its growth.
The changes in the environment and the natural calamities are density independent factor.