The endosymbiotic theory to explain the origin of which structures?

Which of the following best describes the purpose of technology?

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.

Which blood cell spend most of their time in the lymphatic system?