If a plant has xylem and phloem, then the plant is best described as: A: nonflowering
B: vascular
C: flowering
D: nonvascular

i would say it is

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.