1. You decide to test whether charcoal helps purify water or not. You design a filter that contains charcoal and run water from a nearby stream through the filter. Afterward, you test the water for contaminants. Independent variable:
Dependent variable:
This is science I need the answer ASAP please

Is it true or false i’m trying to pass this test so i can leave school

What is the absolute value of the complex number -4-sqrt2i

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.