Cephalochordata is the subphylum that retains all chordate characteristics, even in the adult forms.
All cells are surrounded by the he plasma membrane! The membrane is composed of a philosopher bilayer
Carbon can form single, double, and triple bonds with other carbon atoms.
The correct answer is: d. it contains many light-sensing columns called ommatidia
Ommatidia are units that form compound eyes of arthropods such as insects, crustaceans and millipedes (these are invertebrates) and make them very sensitive to motion. Ommatidia are composed of photoreceptor cells (visual detection) surrounded by support cells and pigment cells.
The eyes of vertebrates are more complex showing that progressive improvements in the structure of the eye occurred during the evolution.
