Both are equally important. Science lets you understand the world, and engineering lets you use your understanding of it, and apply it into inventions and machines that help our lives. (or worsen them) If you just have science, you have all this understanding of physics and biology and you can't do anything with it, it's just knowledge. You know how you could combine these different compounds to make a medicine, but then you can't make it because you can't visualize how to make the machines to synthesize this medicine. You understand how steel and cement could be used to make a sturdy building, but you can't visualize the best possible way to arrange these materials so an efficient building can be constructed. If you just have engineering, you can't even start building stuff because you have no understanding of how it would work. You try to build a building without an understanding of physics and material science, and the building crumbles. You try to make a medicine, you can try to build all the machines that mix and churn, and cook and heat, but you have no idea what chemicals you need or where to obtain them.