By contrast, postganglionic fibers in the parasympathetic division are cholinergic and use acetylcholine as a neurotransmitter. In the sympathetic nervous system, the postganglionic neurons of sweat glands release acetylcholine for the activation of muscarinic receptors.
The International Space Station (ISS) is made up of multiple materials. Lightweight metals, plastics, and carbon fibers make up the majority of the state. The International Space Station (ISS) is made up of multiple materials. Lightweight metals, plastics, and carbon fibers make up the majority of the state.
What the Core Is Made Of. Considering that the whole Earth on average consists of the same mixture of stuff we see elsewhere in the solar system, the core has to be iron metal along with some nickel. But it's less dense than pure iron, so about 10 percent of the core must be something lighter.