Trees have ligneum tissues which makes them rigid and able to grow tall. They have roots, trunk and crown. Deciduous trees in temperate regions lose their leaves in winter while evergreen trees keep their leaves. In tropical zones, trees are green all year long as new leaves replace old.

Originally released by QA International, 2006. Streaming video file encoded with permission for digital streaming by Infobase on May 06, 2015.

Trees (2:00); .