precursors

Chemical precursors are largely sourced from chemical companies in China that sell their products internationally.

Tiny, primitive and sometimes quite strange, they were the precursors of the thousands of different mammals living today, from cats to humans to whales.

Although invertebrates do have the opioid precursor proenkephalin and some other signs of precursors to the opioids found in vertebrates like us, endorphins as we know them evolved in vertebrates.

To make them, the researchers start with the liquid precursors of glassy polymers and mix them with an ionic liquid.

"Atmospheric chemistry is complex, and climate change affects the rate of chemical reactions, the amount of ozone precursors present, and how long the ozone will linger in the environment," Garcia Menendez says.