Which of the following is true about conservation and preservation?
I. Protects the ecosystem from destruction
II. Prevents the depletion of natural resources.
III. Maintains the population of endangered plants and animal species.

The correct option is B I, II and III

Conservation is the sustainable use and management of natural resources, both renewable and non-renewable. Preservation is the strict keeping aside of natural resources so as to prevent the use or contact of resources by humans or by human intervention.

Conservation ensures that resources are not consumed faster than they can be replaced. It also ensures that sufficient quantities are maintained for future generations to utilise. Thus, it is involved in preventing the depletion of natural resources.The main purpose of conservation and preservation is to protect the ecosystem from destruction due to increased use of or consumption of resources. Conservation is also carried out to protect plant and animal species from being extinct. It maintains the population of endangered species by protecting and restoring the habitats and maintaining the essential ecological processes and life-support systems.

Thus, the correct answer is option D.