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

that would be called plucking : )

explanation:

''plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large "joint blocks". as a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock."