To solve this problem, we need to analyze the given statements:$\newline \bullet$Statement I: Endarch and exarch are the terms often used for describing the position of secondary xylem in the plant body.$\newline$ - Endarch and exarch are terms used to describe the arrangement of primary xylem, not secondary xylem.$\newline$ - In endarch arrangement, the protoxylem is towards the center and metaxylem towards the periphery, typical of stems.$\newline$ - In exarch arrangement, the protoxylem is towards the periphery and metaxylem towards the center, typical of roots.$\newline$ - Therefore, Statement I is incorrect.$\newline \bullet$Statement II: Exarch condition is the most common feature of the root system.$\newline$ - In roots, the xylem is typically exarch, meaning the protoxylem is located towards the periphery.$\newline$ - This is a characteristic feature of root systems.$\newline$ - Therefore, Statement II is true.$\newline$Based on the analysis, the correct answer is:$\newline$Option 4: Statement I is incorrect but Statement II is true.