The renewable resource among petroleum, wood, iron, and coal is wood.

What “renewable resource” means

A renewable resource is one that can be naturally replaced on a human time scale, such as within years or decades instead of millions of years.

Examples include wood from forests, as trees can be replanted and grown again if managed sustainably.

Why wood is renewable

  • Trees can regrow through natural regeneration or replanting, making wood replenishable with proper forest management.
  • Many school and exam questions explicitly list wood as the correct answer when asking which is a renewable resource among petroleum, wood, iron, and coal.

Why the others are not

  • Petroleum: Forms over millions of years from ancient organic matter, so it cannot be replaced quickly and is considered nonrenewable.
  • Coal: Also takes millions of years to form and is definitively classified as a nonrenewable energy resource.
  • Iron: Exists as a finite mineral in Earth’s crust; once high‑grade ores are extracted, they do not regenerate on human time scales, so iron ore is treated as nonrenewable.

Answer: wood is the renewable resource.