Vehicle ownership by expats in Saudi. Public transport is almost negligible in Saudi Arabia. As an expatriate, it is really convenient if you have a car of your own. For those of you with your families, it is almost impossible to survive without a vehicle.
Phyla with a true coelom and digestive system are divided into two groups, the protostomes and the deuterostomes. As the hollow sphere of cells known as a blastula develops, an invagination produces an opening called the blastopore. In protostomes, the blastopore becomes the mouth.
The phylum Annelida, segmented worms, is characterized by the possession of a coelom (body cavity), setae (moving bristles), and a body divided into segments by transverse rings. The class Polychaeta, meaning many hairs, is a large and extremely diverse group with more than 6,000 living species.