Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions.

Those who are concerned with protecting the environment often use the words conservation and preservation. These two terms are often confused and are used to mean the same thing, although differences exist.

Conservation is the sustainable use and management of natural resources including wildlife, water, air, and earth deposits. Natural resources may be renewable or non-renewable. The conservation of renewable resources like trees involves ensuring that they are not consumed faster than they can be replaced. The conservation of non-renewable resources like fossil fuels involves ensuring that sufficient quantities are maintained for future generations to utilise. Conservation of natural resources usually focuses on the needs and interests of human beings, for example the biological, economic, cultural and recreational values such resources have. The rain forest for example, contains a wide range of biodiversity, providing food stocks for local populations and a source of timber and medicines for other countries. Conservationists accept that development is necessary for a better future, but only when the changes take place in ways that are not wasteful. What the conservationist opposes is not the harnessing of nature for mankind's progression, but the fact that all too often the environment comes off the worse for wear.

Preservation, in contrast to conservation, attempts to maintain in their present condition areas of the Earth that are so far untouched by humans. This is due to the concern that mankind is encroaching onto the environment at such a rate that many untamed landscapes are being given over to farming, industry, housing, tourism and other human developments, and that we are losing too much of what is 'natural'. Like conservationists, some preservationists support the protection of nature for purely human-centred reasons. Stronger advocates of preservation however, adopt a less human-centred approach to environmental protection, placing a value on nature that does not relate to the needs and interests of human beings. Deep green ecology argues that ecosystems and individual species should be preserved whatever the cost, regardless of their usefulness to humans, and even if their continued existence would prove harmful to us. This follows from the belief that every living thing has a right to exist and should be preserved.

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The word "assets" in the passage is closest in meaning to ____.