Why is transport of materils necessary in plant or in an animal? Explain

Dear Student,
It because of meeting the requirement of the individual cell and tissue providing them the nutrients and removal of waste.
Please read futher at the following links
https://www.askiitians.com/biology/transport-in-plants/
https://www.askiitians.com/revision-notes/class-7-science/transportation-in-animals-and-plants/