The term "Green Revolution" refers to an increase in agricultural productivity through various methods. Option 1, creation of grasslands, is not an accurate explanation of the Green Revolution. Option 2, planting more trees, while beneficial for the environment, is not specifically related to the Green Revolution. Option 3, enhanced agricultural productivity per hectare, is the correct answer. The Green Revolution was characterized by the introduction of new crop varieties, improved irrigation techniques, and the use of fertilizers and pesticides. These advancements led to significantly higher crop yields, allowing for increased food production to meet the growing global demand. Option 4, creation of gardens in urban areas, is unrelated to the concept of the Green Revolution.