Go to the Prenatal Testing page for more details. If one parent has sickle cell trait (HbAS) and the other has sickle cell anaemia (HbSS) there is a one in two(50%) chance that any given child will get sickle cell trait and a one in two chance that any given child will get sickle cell anaemia.
The defining characteristic of the intertidal zone is that it is submerged with water during high tide and exposed to the air during low tide. The zone can take many forms, from sandy beaches to rocky cliffs. It is common for the intertidal zone to change frequently, since it is constantly battered by crashing waves.
Hope this helped.