What causes a two headed mutation or is this a malformation?

It is also possible for two separated embryos to incompletely fuse to form a two-headed animal. Two-headedness results from factors that cause malformation of a developing embryo, which can be both genetic or environmental. ... A two-headed bullshark caught in waters off the Florida Keys in the US

Explanation:

Its a mutation

the wetland preservation movement began in the u.s. in earnest with the clean water act (cwa) of 1972. although not specifically written to protect wetlands, the cwa is comprised of a series of regulations designed to prevent pollutants from contaminating u.s. waters.