It is important to be careful when using nonrenewable resources because:

• A. their use increases the supply of renewable resources
• B. they cannot be replenished once depleted
• C. they are not affected by market demand
• D. they are always less expensive than renewable resources

Answer: (B)

Verified step by step guidance

1. Understand the definition of nonrenewable resources: these are natural resources that cannot be replenished or regenerated on a human timescale once they are used up.
2. Recognize that because nonrenewable resources cannot be replenished, their availability is limited and decreases as they are consumed.
3. Consider the economic implication: since the supply of nonrenewable resources is finite, overusing them can lead to scarcity and increased costs in the future.
4. Contrast nonrenewable resources with renewable resources, which can be replenished naturally over time and thus have a more sustainable supply.
5. Conclude that the key reason to be careful with nonrenewable resources is that they cannot be replenished once depleted, making their management crucial for long-term economic and environmental stability.