3. Quote the sentence(s) in the
passage meaning that
fertilizers are different and
some are not good for soil.
4. What happened after the
discovery of the NPK in the
mid of 1800s?
5. What are examples of
macronutrients and
micronutrients mentioned in
the passage?
6. Why didn’t the scientists apply
micronutrients to the development
of the soil heath?
7. What is unsustainable farming?