People who have to avoid certain wheat and grain products or have been born without the ability to digest gluten have

The correct answer is Celiac or Coeliac disease.

Celiac disease is when your body is unable to digest gluten. When people with this condition do ingest gluten, so for example bread, their body reacts by launching an immune response and attacking the small intestine. It is classed as an autoimmune disorder. It is hereditary but people can also develop it at any age.

the plates spread at mid-ocean ridges (they are divergent plate boundaries) which allows magma to rise through the weakness between the plates. the magma then emerges as lava from the boundary and cools, creating a new crust.