What is the function of a control group in an experiment? A. It is the group that always changes
B. To check the validity of an experiment
C. To test on the hypothesis of an experiment
D. It is the group that never changes

What is the chemical formula for the compound formed between sodium and flour one

Why do electrons further from the nucleus have more energy

According to the passage, which of these is true about gray water systems? a) gray water systems use plants that require less water. eliminate b) gray water systems require the use of less fossil fuels. c) gray water systems reduce the amount of fresh water used. d) gray water systems reduce the amount water used by shower heads.