| Term B is a part of term A during the time at which they both exist.
Term A may have a part B during the time at which they both exist.
is a type of
| Term B is a type of term A. Term A has subtypes B and C.
| Structure A develops from structure B. Structure B develops into structure A. There
can be a one to one, one to many, or many to one correspondence. For example, structure A develops from
structure B and C, or structure A develops into structure B and C.
|These relationships are representations of formal types described by the OBO-REL ontology: http://www.bioontology.org/wiki/index.php/RO:Main_Page