Answer:
a. overuse of resources is the correct answer.
Step-by-step explanation:
Renewable resources are available and they are abundant but overuse of these renewable resources will have a negative effect on the surroundings and humans.
Overuse of renewable resources will leads to the depletion of these renewable sources in the future and will also make the ecosystem unbalance.
Renewable resources are solar energy, geothermal energy, biomass energy, wind energy, hydro energy.
Thus renewable resources are threatened due to overuse and it must be carefully used.