Question

Why an xylem & phloem called complex tissue.How are they different

Answer 1

Xylem and phloem are called complex tissue because they are made of two or more than two types of cells.
They are different in the following ways:
1 Xylem conducts inorganic material and water while as phloem conducts organic material
2 Xylem conducts only in one direction i.e upwards while as phloem conducts in both directions i.e upward as well as downward
3 Xylem provides mechanical strength to a plant body while as phloem do not ..

Answer 2

they are known as complex tissues because they are made up of more than one type of cell.these cells work in a coordinate manner,as a unit to perform the various functions of the xylem and phloem.