biology, n.Trivia

Algae is neither plant, animal or bacteria. It is a photosynthesizing microorganism.

A virus is not exactly alive. It is an inert packet of chemicals without a host -- it has no cells, no ability to turn food into energy,

There are microscopic living things in solid rock up to 7 km deep, called Endoliths. So little energy is available they undergo cell division once every 100 years, and some may only divide once every 10,000 years.