- the posterior opening of the digestive tract is called an _________
- which have more complex body systems, free-living or parasitic roundworms?
- roundworms exchange gases and excrete metabolic wastes through their ___________
- TRUE OR FALSE:All roundworms develop from three germ layers
- TRUE OR FALSE:Mollusks usually have an interal or external shell
- TRUE OR FALSE: Free-living flatworms have organ systems for digestion, excretion, response, and reproduction
- TRUE OR FALSE:Free-living flatworms often have complex life cycles that involve both sexual and asexual reproduction
- a fluid filled body cavity that is lined with tissue derived from mesoderm is called a _______
- Terms qualifying types of reinforcement and punishment
- sea stars, sea urchins; radial symmetry, digestive tract, gills, open circulation.
- Have a mouth and anus, bilateral symmetry and also moist skin and cold blood. They lay eggs in water.
- Have a mouth and anus, bilateral symmetry and also feathers, warm blood and scaly legs
- Live attached to rocks, filter feeders, multicellular, no symmetry.
- Have a mouth and anus, bilateral symmetry and also fur, warm blood, and feed young on milk.
- Have a mouth and an anus, bilateral symmetry and all groups have a notochord - a central primitive axis of the embryo (a primitive backbone)
- Have a mouth and anus, bilateral symmetry and also scales and cold blood. Eggs can be layed on land.
- Have a mouth and anus, bilateral symmetry and also scales and cold blood. They lay eggs in water.
- Mouth and anus, bilateral symmetry, visible blood vessils.
- Multi-celled eukaryotic heterotrophs without cell walls
- Not segmented, soft bodies with shells, mouth and anus. foot has bilateral symmetry.