The ideal of science is objectivity. To be objective is to be truthful, to describe the world as it actually is. If the ideal of objectivity were perfectly realized, then science would give us a complete description of the world. But this is impossible. The world is infinitely complex, and description is always finite.
Every investigation ignores most of what is there.
What scientists study depends upon what they regard as important. Their judgments of what is important are shaped by their predilections, their scientific training and their economic and political interests. The decision to investigate or not investigate a particular problem is not determined by objective criteria. Universities and charitable foundations also fund research directly, but have much smaller budgets. Hence government and industry have considerable influence in deciding which questions are asked.