Final answer:
Elements heavier than iron are formed in supernova explosions, a fact supported by spectroscopic analysis of supernova remnants like Supernova 1987A.
Step-by-step explanation:
The statement that the elements heavier than iron in Earth were formed by the supernova explosions of other stars is true. Within stars more massive than about eight solar masses, nuclear reactions create new chemical elements, known as nucleosynthesis, up to iron.
However, elements heavier than iron require the intense conditions of a supernova to form. During these colossal explosions, the nucleus of iron and other lighter elements capture neutrons, leading to the creation of these heavier elements. Subsequently, these materials are dispersed into space where they can contribute to the formation of new stars and planets. Spectroscopic analysis of supernovae remnants, such as Supernova 1987A, confirms the presence of these heavier elements created during the supernova events.