stylistic:tone
Chemicals

Many pharmaceuticals are derived from petroleum, albeit via multistep processes. Modern medicine depends on petroleum as a source of building blocks, reagents, and solvents. Similarly, virtually all pesticides - insecticides, herbicides, etc. - are derived from petroleum. Pesticides have profoundly affected life expectancies by controlling disease vectors and by increasing yields of crops. Like pharmaceuticals, pesticides are in essence petrochemicals. Virtually all plastics and synthetic polymers are derived from petroleum, which is the source of monomers. Alkenes (olefins) are one important class of these precursor molecules.