Codominate? I'm not sure if that's what your asking, the question is kinda unclear.
Chromosomes. and these words are only because it needs to be 20 characters
Answer:
Sinoatrial Node?
Explanation:
Blood pressure drops whenever the vagus nerge is stimulated. In fact, babies have to constantly be monitored for position, becase cranial pressure can stimualte the vagus nerve and cut heart circulation by inhibitng the Sinoatrial node.
In this kind of population, the make up of the population's gene pool will remain virtually the same as long as these conditions hold. In this kind of situation, no evolution can take place, all thing will remain the same. For evolution to occur, competition must exist.
The answer is a. the abiotic components of an ecosystem