Pl help If you could add any building item options to your virtual train to improve its design, what would
those items be and why would you need to add them?

thats not even an aswer choice

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.