question_answer

You are given a fairly old piece of dicot stem and a dicot root. Which of the following anatomical structures will you use to distinguish between the two? [AIPMT 2014]

A)  Secondary xylem-  

B)  Secondary phloem

C)  Protoxylem        

D)  Cortical cells

Correct Answer: C

Solution :

In dicot stem the protoxylem is present towards center (pith) and metaxylem is present towards the periphery of the organ. This type of xylem is known as endarch. In root. The protoxylem is present towards periphery and metaxylem present towards center that is called exarch.