Why are xylem and phloem called complex tissues?
(a)Both xylem and phloem consist of one type of cells which coordinate to perform a common function
(b)Both xylem and phloem consist of more than one type of cells which coordinate to perform a common function
(c)Both xylem and phloem consist of more than one type of cells which do not coordinate
(d)Both xylem and phloem consist of one type of cells which gives strength to the plants