But very soon one cell starts to give off chemicals unique to itself.

But with prolonged oxygen deprivation for many minutes, cells start to die.

This causes cells to start to die from oxygen starvation.

How exactly did cells start to die off consistently in the right places?

Within 72 hours, the cells had stopped growing and were starting to die.

That one cell starts to divide, but the subsequent cells are different.

As soon as cells start to die and begin to need to be replaced.

All agree that the cells took up the genes and started using them.

Indeed, the cells actually started making more of the stuff.

When the heart is deprived of oxygen, its cells start to die.