Question

proto xylem and metaxylem explain endocrine and exocrine conditions of xylem

Answer 1

In  stems, the protoxylem lies towards the centre (pith) and the

metaxylem lies towards the periphery of the organ. This type

of primary xylem is called endarch. In roots, the protoxylem

lies towards periphery and metaxylem lies towards the centre.

Such arrangement of primary xylem is called exarch.