Which of the following is not a technology that can be used to conserve resources?
a. hydropower
b. volcanic power
c. natural gas
d. geothermal

The correct answer to this question is c. natural gas.

A renewable resource is a substance of economic value which can be replenished or replaced either through natural recurring processes or biological reproduction.
Biomass is a biological material taken from plants or plant-based materials.Biomass is considered a renewable resource because plants and plant-based materials can be found everywhere and once used these plants will continue to grow and supply the demand for biomass consumption.

b. volcanic power

Explanation:

The volcanic power is not any technology that can be used to conserve the natural resources as the presence of the volcanic eruption is itself a natural environment is by itself a valuable resource but the power that heats up the landscape can it be used to tune up the natural resources of the country. Thus the impact so the natural resources cannot be eliminated due to the use of the vents of the volcanoes. though this not related to the convention or not conventional reduces the country.

Which one is the underlined word?

It is the second answer