In essence, this is where the beauty of Geology & Physical Geography lies - they tremendously compliments Evolution & Biology [& vice versa.]

But going back to radio-active decay of Iron deep within the earth's core, thank God it's really deep within the earth's core or else, there wouldn't be any living matter here if that massive decaying Iron is at the surface as everything then would've been obliterated by its enormous heat only the sun can match!

However, radio-active decay (as long as it's deep within a planet's core) is what gave life to all the living creatures of this planet which is what makes Earth unique 'coz all the other planet in the solar system are radioactively DEAD & thus, has no life.

Ah, but I'll get to that story in later articles since the writing here has already gone too long!