What is the name of the substance whose accumulation in the pelicans of Lake Michigan led to the formation of thin shells of their eggs?

DDT accumulated in the pelicans of Lake Michigan and thinned their eggshells, causing breeding failure.

CFCs are refrigerant gases that deplete stratospheric ozone, not eggshell thinners in birds.

PAN is peroxyacetyl nitrate, a component of photochemical smog, unrelated to this effect.

PAC does not name the pesticide behind the thin shells.

DDT builds up through biomagnification, reaching high levels in top predators like fish-eating birds.

This finding helped drive the ban on DDT in many countries.