The question is incomplete as it does not have the options which are:
artificial
enhanced natural
extraterrestrial
manmade
Answer:
Enhanced natural resources
Explanation:
Natural resources are the resources used by the humans for survival present in the environment or provided by the surrounding environment.The natural resources includes the wood, gas, air, water and other substances.
The substances which emits harmful radiations like radium, thorium, uranium are known as radioactive isotopes.
When these ionizing radiation emitting natural substances increases in the environment due to human activities like the particle accelerators, X-rays and other methods which produces these substances then these substances are refereed to as the enhanced natural substances.
Thus, Enhanced natural resources is the correct answer.
