The main way in which artisan guilds changed labor and social class in medieval Europe is that it gave the artisans, who were mostly members of the lower class, more power--since these guilds acted somewhat like a modern "union" and helped them negotiate better pay.
Answer:
A) They are named for the places where geologists first described rocks or fossils from that time
Explanation:
The relationship between plant and animals, layers and types of rocks, fossils and radioactive dating are used for preparing Geologic Time Scale. Geologic time is comprise of four Eons namely Hadean (the initial stage) followed by Archean and Proterozoic and Phanerozoic in the recent . The Eons are classified into eras and theses eras reflect the changes in fossil record. Eras are further divided into periods and some periods into Epochs.
In periods a single rock system is found while the division in the era's reflect major changes in fossil record.
