Plants and animals are living things. They come to life, grow and change. Every living thing dies at some time, plants and animals alike. When a living thing dies, its body stops working. A body that has died does not start working again. Dead is forever. That is the plain truth, and it is fine to say it out loud and to ask about it. But a lot still happens to a body after that.

Dead plants and animals are food for decomposers, such as bacteria, fungi and earthworms. Decomposers break dead things down into nutrients that go back into the soil, where plants can use them again. Without decomposers, waste would pile up. They are nature's recyclers.

Take the earthworm. Earthworms eat dead plants and animals, and they loosen the soil as they burrow. Their droppings, called casts, are rich in nitrogen, phosphorus and potassium, which help plants grow.

Fungi and bacteria do the smallest work. Fungi cannot make their own food. They release enzymes that break down dead plants and animals. Fungi can even break down tough parts of wood and plants, such as lignin, chitin and cellulose. Bacteria are tiny living things too. The ones that live on dead material break it down into nutrients that go back to the soil. Each one has a job.

A fallen dead tree can become a nurse log. New baby trees grow on it, getting shade, nutrients and water. Fungi feast on a decaying tree, and fungi and bacteria help break down lignin, the tough stuff in wood. Squirrels roost on or in nurse logs, and bats have been found using tree stumps. A dead tree is full of life.

The sea has its own clean-up. When a whale dies and sinks to the sea floor, its body feeds deep-sea animals. This is called a whale fall. Scavengers such as sharks, hagfish, rattails and crabs eat the flesh off the bones. They eat the soft parts in a matter of months, and then different animals arrive. A whale fall is an oasis of food on a deep-sea floor where food is often hard to find.

After Pacific salmon lay their eggs, they die. Their bodies feed scavengers or rot, adding nutrients to the stream. Scavengers such as vultures and sea eagles find dead animals quickly and eat them. Scavengers do not leave much for long.

Most dead plants and animals decay or get eaten, so only some become fossils. How does a fossil start? A fossil often starts when a dead plant or animal is buried quickly by mud, sand or ash. Soft parts rot away and hard parts such as bones, teeth and shells are left behind. Over time the mud and sand harden into rock, and water full of minerals soaks into the remains and can turn bones to stone.

Lives come in many lengths. An adult mayfly does not eat and lives only a day or two, long enough to mate and lay eggs. Galapagos tortoises can live to be over a hundred years old. A clam called Ming was 507 years old when it died in 2006. Each of these lives ends, and each is part of the same story. Some lives are short and some are very long, but every one of them ends.

People and families believe different things about death. Ask yours. When something dies and it makes you sad, or you have questions, talk to a grown-up you trust, such as a parent, a teacher or a school counselor. They want to hear what you wonder. Asking is a good thing to do.

Words to know

• decomposers: dead-matter eaters
• nutrients: plant food
• fungi: mushroom family
• scavengers: leftover eaters
• fossil: stone remains