Answer:
1. presence of dorsal cord or notocorde in some stage of development, its function is sustained and is dorsal to the digestive tract.
2. They have a nerve cord covered by a skull, this cord is hollow and tubular and is dorsal to the digestive tract.
3. posttanal tail
4.Both have a closed circulatory system
5.They reproduce sexually
6.Complete digestive system, with mouth and anus