If you start be assuming the result and then reject any other possibility, then you are doing what Popper warned against.
So the open approach is not take for granted, that science can't explain everything and ask questions in such a manner, that you allow for the possibility that science can't explain everything.
Where did you get the bloody stupid idea that science is meant to answer or explain every questions???!!!
Science or on inquiry, investigating and testing the natural or physical world.
It always start with preliminary observation, followed by attempting to explain what had being observed.
Such explanation will attempted to address several key questions, as to WHAT it is, HOW does it work, and if possible, HOW do we make use of such knowledge. This part is the formulation part of the hypothesis (of the scientific method), which may include mathematical model that either represent the nature of phenomena or to serve as a predictive tool for possible ways of could work, that may help with setting up the baseline for testings (eg observation via evidences gathering or controlled environment for experiments).
The testing stage (of the scientific method), is to test evidences gathered and accumulated, or attained data from test results of performed experiments. The evidences or test results would allow the researcher to compared them and analyzed them against the explanation and predictions of the hypothesis.
It is these evidences, test results and data that will determine if the hypothesis is probable true or probable false, or respectively verified/validated or refuted; the conclusion can be only reached if there evidences/data are in sufficient quantities to determine probability.
If the hypothesis survive through falsifiability and scientific method, then it may have chance of passing scrutiny of the Peer Review, and possible elevation of the hypothesis to scientific theory status.
But any falsifiable hypothesis or scientific theory are inerrant or infallible. They can be challenged, changed/updated, or replaced by better alternative hypothesis/theory.
To give you an example. Charles Darwin had proposed the concept of biodiversity over time, through Natural Selection, but his death, the theory of evolution has been corrected and updated by other biologists over the decades and over a century-and-a-half, through the accumulation of more evidences that support the Natural Selection mechanism.
But the theory of evolution, have expanded beyond Darwin’s original, to include other different mechanisms, eg Genetic Drift, Mutation, Gene Flow and Genetic Hitchhiking. Advances in biology have our allow biologists to better understand evolution, such as molecular biology, DNA, the genome project, and for understanding human evolution, the Y chromosome DNA haplogroup and mitochondrial.
All of this, took time, to learn and understand, for technology to catch up and to help biologists and related fields to do their works.
There are still more to learn, therefore, biology don’t know every single things.
I don’t think you understand science as much as you think you do, if you think science is supposed to explain everything.