eli5 What actually makes a fruit “ripe”?

Question

Title. In addition, why does fruit become even sweeter when it ripens?

In: 5

Answer 1

Fruits are ripened by plants releasing hormones; a common one is a gas called ethylene.

Ripeness typically gives a bright colour along with the added sweetness; both of which make the fruit more attractive to a passing animal, which will eat it and then poo out its seeds somewhere else, allowing new plants to grow in other locations.