The last one will be It's better to use the average data instead of the single trail because the average you don't have to multiply add subtract and all that nonsense but if you use the single trail you will have to do all the adding multiplying etc.
This allows us to visually see the structure of the atoms/ molecules so we can get a better understanding of what they look like.
The information that a foliated metamorphic rock provide about the conditions it was formed under are:(for many diffrent rocks like Phyllite and Amphibolite)
you can tell by its features like if its smooth and sleek or if its rough and bumpy those physical features.