20. The earliest animals on Earth had either asymmetrical bodies or radial symmetry, but many animal lines eventually adopted a cephailzed body with bilateral symmetry. What were the advantages of this new body plan

c.           is the correct answer

a. an idea which cannot be disproven!

explanation:

garbage disposal because lysosomes dispose of old cell parts like garbage disposals dispose of old food.

the species living around the vents are especially good at dispersal.  

deep-sea vent originates on the floor of the ocean when seawater circulates through hot volcanic rocks, usually situated where the new oceanic crust is being produced.  

biological dispersal refers to the movement of species from their location of birth to their site of breeding, or from breeding site to another. similarly, the oceanic dispersal refers to the movement of the species from one land mass to another by sea crossing.