Final answer:
On the Balance Error Scoring System (BESS), taking a step and opening eyes simultaneously are both counted as separate errors, making the statement true.
Step-by-step explanation:
The Balance Error Scoring System (BESS) is used to measure an individual's balance. According to the rules of the BESS, if an individual takes a step and opens their eyes while in a position where they should remain still and eyes closed, each would be counted as separate errors. Therefore, the statement is true; simultaneously taking a step and opening eyes would be counted as two errors on the BESS assessment.