In South Africa sedimentary rocks of Archean age have been found with rounded pyrite pebbles, which are not found in sedimentary rocks today. What is the most likely reason for this?

W) Pyrite is no longer formed on Earth's surface

X) Liquid water was not present during the Archean

Y) Atmospheric oxygen levels were very low in the Archean

Z) Atmospheric pressure was lower in the Archean
Y) ATMOSPHERIC OXYGEN LEVELS WERE VERY LOW IN THE ARCHEAN17) Physics - Short Answer The statement that all points on a wave front will serve as point sources for secondary waves is based on what principle or theory?