An important effect that hunter-gatherer societies may have had on the environment was: a. soil erosion
b. extinction
c. air pollution
d. all of the above

Hmm.

Explanation:

A. Soil erosion

Habitats were destroyed as grasslands, forests, and wetlands were replaced by farmland (this can cause erosion and floods and lead to soil that is no longer fertile).

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation:

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.