Answer:
Reading, talking and walking.
Explanation:
Natural environment constitute all the living and non-living things present in the earth. Human's activities has destroyed the natural environment and the organisms living in that environment.
Deforestation, industrialization and urbanization has drastically affected the environment. Reading, walking and talking does not affect our environment because no energy is wasted or trees are cut down during these activities.
Thus, talking, walking and reading does not harm our environment.
