Mutual
mutual
They can be.
If two organisms share an evolutionary relationship, that means that they have a common ancestor on the evolutionary tree. The more recently the shared common ancestor lived, the more closely related the two present organisms are, evolutionarily.
Covalent molecule.
common multiples
one
If two organisms share an evolutionary relationship, that means that they have a common ancestor on the evolutionary tree. The more recently the shared common ancestor lived, the more closely related the two present organisms are, evolutionarily.
Contiguous means that two or more physical areas share a common border, such as two neighbouring countries such as France and Spain or Portugal and Spain. Non-contiguous means that there is no shared or common border, as is the case between France and Portugal.
A common multiple
In an electron dot diagram, two pairs of shared electrons between two atoms indicate a double covalent bond. This means that the two atoms are sharing two pairs of electrons to achieve a stable electron configuration.
A molecule or a compound.
A vertex is the shared endpoint of two or more line segments.