Help with 1,2,3 WILL MARK BRAINLIST

Which is the solubility product expression for caf2(s)?  [ca2+]/[f–]2  [ca2+][f2–]  [ca]+[f]2  [ca2+][f–]2

Why do lunar and solar eclipse not happen every month

Which of these is an example of pseudoscience? a) predicting the time of sunrise based on data on position of earth b) predicting the date of the moon phases based on data on position of earth c) predicting eclipses based on the position of the sun and the moon d) predicting future events in a person's life based on the position of the moon