Which statement about coal is true? when burned, coal produces pollutants that are released into the air. coal will always stay plentiful in the united states. mining coal improves the environment. burning coal does not pollute the air.

When conducting an investigation to determine which type of fertilizer produces the most flowers on a plant, which variable would be graphed on the x-axis once you collected the data? a. type of fertilizer b. amount of flowers c. amount of water d. number of days that the plants grew