Explanation:
In neurology, postganglionic nerve fibers are autonomic nerve fibers from the ganglion to the effector organ. These, unlike preganglionic fibers (whose sole neurotransmitter is acetylcholine) have a variety of neurotransmitters to fulfill their functions.
Neurotransmitters
The neurotransmitters of postganglionic fibers are varied, and are distributed as follows:
In the parasympathetic nervous system, neurons are cholinergic (Acetylcholine is the primary neurotransmitter)
In the sympathetic nervous system, neurons are mostly adrenergic (norepinephrine-epinephrine and / or norepinephrine, both have the same chemical structure, but epinephrine has a methyl group unlike norepinephrine that has a hydrogen, instead of a methyl group - act as the primary neurotransmitter) Two exceptions to this are the sympathetic innervation of the sweat glands and the piloerector muscles where the neurotransmitter in both pre and post ganglionic synapses is acetylcholine and in the vessels of the renal cortex where dopamine is used as the main neurotransmitter. Another exception is the sympathetic innervation of the medulla of the adrenal gland, which is innervated by preganglionic fibers, and subsequently uses acetylcholine as a neurotransmitter. Adrenal medulla cells are, in fact, modified postganglionic neurons that secrete epinephrine and norepinephrine directly into the bloodstream rather than a synapse.
In both divisions of the autonomic nervous system, postganglionic neurons express nicotinic acetylcholine receptors to receive signals from preganglionic neurons.
The <span>Endoplasmic Reticulum </span> have to control and transport material to other places.
<span>This is a positive feedback. These episodes make the next glacial period even more severe and long-lasting than the one prior. This is due to the reflectance of the surface of the land having a positive relationship with how much energy is absorbed: as the reflectance increases, absorption decreases, and the glacial period increases in severity.</span>
The hotspots are regions, where the plumes of magma are present just below the lithosphere. The plume of the magma is the particles of the volcano and the gases, which is erupted during the volcanic eruption. It is generated by the fragmentation of the magma. Once, it reaches the lithosphere, it get spreaded laterally.
The plumes at the hotspots are present just below the tectonic plates, a high temperature r heat and the low pressure causes the rocks present in the lithosphere to melt resulting in volcanic eruption. At hotspot, the melting of rock takes time, sometimes it is very slow, due to the presence of various tectonic plates. Hence, the plumes can remain stationary for a very long period of time without erupting.
So, the first blank can be filled with Lithosphere and the second blank can be filled with Stationary.
The affinity of unrelated plants
to evolve superficially in similar characteristics under similar environmental
conditions like climates but separated by distance are influence by convergent
evolution. Seed dispersal has evolved independently in most plant
species. For instance, the fleshy part of a tomato is the walls of the outer
layer. This implies convergent evolution under selective pressure where competition
for seed dispersal is through consumption of fleshy fruits by animals such as
birds or ants.
