- Life Sciences
an informal term for any living species which appears to be the same as a species otherwise only known from fossils and which has no close living relatives. These species have all survived major extinction events. The coelacanth is an example of a living fossil.
when the entire heart, both of the atria and ventricles, is relaxed.
the practice and science of classification. This is the part of systematics that is only...
a strong ring of smooth muscle at the end of the pyloric canal which lets food pass from the...