Answer:
All cells are surrounded by a cell membrane. The cell membrane is semipermeable, allowing some substances to pass into the cell and blocking others.
Explanation:
Echinoderms evolved from bilateral ancestors and they are bilateral in their free swimming juvenile life stage. As adults they assume a pentamerous or radial symmetry by metamorphosis of juvenile to adult form.
<span>Weight, should be "The force on an object due to its mass and gravity"
hope this helps</span>
The medical term that means of or pertaining to a position toward the belly of the body; frontward; or anterior is= Ventral
