Question

Think of an example where nature allows one organism to live and another to die.

Answer 1

Maybe Parasitism

Answer 2

Parasitism's a good example.

The only thing is that parasitic relationships don't ALWAYS result in the death of an organism.

Humans, for example, can contract parasitic diseases, and live.

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Have you heard of "natural selection"?

NATURAL SELECTION is where NATURE decides who lives, and who dies.

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Here's a pretty well known example:

There's an island.

And on the island, there are two types of birds:
ones WITH sharp beaks,
and ones WITHOUT sharp beaks.

And on the island, the birds' main source of food
is nuts, that have hard shells.

In order to eat the nuts,
the birds have to first crack them open, using sharp beaks.

But WAIT!
Some birds don't have sharp beaks!
So what happens to them??

Answer: They die.

That is an example of NATURAL SELECTION.

NATURE and the ENVIRONMENT decide who lives, and who dies,
based on the organism's physical features.