How do you call the division of earth's history into manageable parts?

Analyze the central conflict and its in a story to discover the theme. o resolution o protagonist antagonist character

Based on the law of dominance, we would expect percent of the offspring from this cross to have large teeth.

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes