Lifespans may be long (more than 30 years) for such small organisms.

The issue of whether there are organisms both large and small, on Mars in particular, is entirely open.

It may also eat other small organisms it comes across.

Once in the water, the mercury is absorbed by small organisms and worms.

They feed by sucking in small organisms of adequate size.

The problem with these smaller organisms is that they're not mammals.

One would therefore expect to see more new species created in small organisms and warm environments.

A bacterium is a very small organism made up of one cell.

It has allowed a researcher to study the behavior of small organisms in a controlled environment.

There are smaller organisms still; many too small to see.