Density-independent factors are environmental factors that affect population growth or mortality rates regardless of population density. These factors have the same impact on population size regardless of the population's size or density. In contrast, density-dependent factors have a stronger impact on population growth as the population density increases.

The correct answer is option A, B, and D. Predation, disease, and parasites are all density-independent factors affecting populations. Let's discuss each option in detail:

a) Predation:
- Predation refers to the act of one organism (predator) feeding on another organism (prey).
- Predation can significantly impact population size by directly reducing the number of individuals in a population.
- The impact of predation on a population is not dependent on the population's density. It can affect populations regardless of their size or density.

b) Disease:
- Diseases can spread within a population and cause mortality or reduce reproductive success.
- Like predation, diseases can have a significant impact on population size by directly reducing the number of individuals.
- The spread and impact of diseases are not dependent on the population's density. They can affect populations regardless of their size or density.

c) A destructive hurricane:
- A destructive hurricane is an example of a density-dependent factor.
- Density-dependent factors are environmental factors whose impact on population size increases as the population density increases.
- A destructive hurricane can cause widespread destruction, including loss of habitat, food sources, and increased mortality, but its impact is more severe when the population density is high.

d) Parasites:
- Parasites are organisms that live in or on another organism (host) and derive nutrients from the host.
- Parasites can affect the health and survival of their hosts, leading to population decline.
- The impact of parasites on a population is not dependent on the population's density. They can affect populations regardless of their size or density.

In summary, predation, disease, and parasites are examples of density-independent factors affecting populations. They can impact population size regardless of the population's density. A destructive hurricane, on the other hand, is an example of a density-dependent factor, as its impact increases with higher population densities.