restriction. n. 1. something that restricts; a restrictive measure, law, etc. 2. the act of restricting or the state of being restricted. 3. (Logic) logic maths a condition that imposes a constraint on the possible values of a variable or on the domain of arguments of a function.
The primitive gut that forms during gastrulation in the developing embryo is known as the archenteron or the digestive tube.It develops into the digestive tract of an animal.ach is controlled by the dorsal blastopore, and primitive node (also known as Hensen's node), respectively. During Gastrulation, the Archenteron develops into the digestive tube, with the blastopore developing into either the mouth (Protostome) or the anus (Deuterostome).
They comprise methane-producing anaerobic species (methano-P. Forterre: The most primitive organisms on Earth 169 yens), bacteria living in very high salt environments (halobacteria) and a huge number of diverse thermophilic species, aerobic and/or anaerobic, acidophilic or neutrophilic (sulfothermophiles).oese first suggested that the universal ancestor was a truly primitive organism, a progenote (Woese, 1981), i.e. an entity representing an evolutionary stage in between the very first living cells and modern procaryotes, fulfilling the dream of evolutionists. However, it turns out that molecular 172 Fig.