1 This is caused when an opening in the abdominal wall, which normally closes before birth, doesn't close completely. 2  If small (less than half an inch), this type of hernia usually closes gradually by age 2. Larger hernias and those that do not close by themselves usually require surgery at age 2 to 4 years.
Segmented worms (Annelida) are a group of invertebrates that includes about 12,000 species of earthworms, ragworms and leeches. Segmented worms live in marine habitats such as the intertidal zone and near hydrothermal vents.egmented worms are classified within the following taxonomic hierarchy: Animals Invertebrates. Segmented worms are divided into the following taxonomic groups: 1  Polychates-The polychaetes include about 12,000 species that are characterized by having multiple hairs on each segment.
Echinoderms make use of tube feet to move them towards their food sources and often use these tube feet to attache to their prey or direct their mouth area toward the food source. Though the digestive systems vary, they are all relatively simple when put into comparison with an organism such as a human.