What do we mean when we say 'prehistory'?
Prehistory is the period of time between the invention of the first stone tools by the first human ancestors around 3 million years ago, and the invention of writing systems. In Britain, this was roughly between 900,000 BCE, with the first human ancestors appearing in Britain, and the Roman invasion in 43CE.
This is a very large stretch of time, and so to make things simpler, we divide prehistory into three main periods: The Stone Age, The Bronze Age, and The Iron Age. These periods have their own sub-categories, for example, The Stone Age consists of the Paleolithic era, The Mesolithic era, and the Neolithic era.
Archaeology can help us understand prehistory, the period before humans left any written records, and can help us to reconstruct an image of their lives, from the food they ate, to the clothing they wore.