destiny, density

Destiny or destiny means fate or predetermined fortune--
He became convinced that losing was his destiny.
She believed in destiny, and was sure that her fate was already decided.

"Destiny", used as a proper noun ( always capitalized ),
 means the power that determines fate, usually represented as a woman or goddess--
He prayed to Destiny to change his fortune.

Density or density means a measure of how crowded or compact something is--
The government is doing a study of population density.
The density of the structures leaves no room for gardens.

Now that you know that, you can say--
"The researcher feared it was his destiny to spend his life studying population density."