Why is the flower so red? In the end, it is due to artificial selection. Natural selection is slow and takes a long time to show its effect. The manual selection has greatly accelerated its process and can achieve significant results in a short time. The history of cultivation is only two or three hundred years, but there are thousands of varieties with different shapes and colors. This passage directly supports the view that. ['The history of artificial cultivation is short, but it is remarkable.', 'Natural selection is not as good as artificial selection.', 'Artificial selection can make the flower redder.', 'Manual selection speeds up the process of flower change.']