Will mark brainliest pls help!

What does PH measure? My belief is it’s hydrogen ions or hydronium ions but i don’t know

Which is a characteristic of mixtures?

How many atoms of mg are present in 97.22 grams of mg? 6.022 × 1023 2.408 × 1024 4.818 × 1024 5.855 × 1025

Scientific evidence tells us that the cause of earths four season is the tilt of earth as it revolves around the sun. the student is instructed to illustrate this information in a science notebook. how will the student illiterate winter in the northern hemisphere?