Anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by
(a) absence of secondary xylem
(b) absence of secondary phloem
(c) presence of cortex
(d) position of protoxylem
Correct option (d) position of protoxylem
Explanation
In dicotyledonous root, the condition of xylem is exarch as the protoxylem is away from the centre and metaxylem is towards the centre. In dicotyledonous stem. (e.g. Cucurbita), the condition of xylem is endarch as the metaxylern is away from the centre and protoxylem is towards the centre.
