The picture on the left shows how a plant stem looks when sliced open, magnified, and viewed from above. The picture on the right shows a sketch of some structures that are inside every human body.

Each picture shows tubes that run throughout the organism.


What is the main purpose of these tubes?
A.
carrying nutrients and wastes

B.
creating speech

C.
taking in and responding to signals from the environment

D.
making flowers for reproduction