In science, a theory is a hypothesis, and a law is a statement of a observed phenomenon proven to be true.
- A theory explains why a natural phenomenon occurs.
- Scientific laws summarize a set of observations about a natural phenomenon that was witnessed.
- Both can be revised, used to make predictions, and are based off of a hypothesis.
Answer:
The fourth plant that receives pure water is the control group.
Explanation:
The election of a control group is essential in an experiment. Its principal purpose is to allow the discrimination of the results obtained by the treatment in the study, in this case, <em>the different concentrations of salty water that each plant receives</em>. The control group provides a reference point. It must be selected from the same population of the treatment groups. Both groups must be similar in every variable that might influence the results, <u>except for the study treatment.</u>
D; because the cells dna is not in the nucleus
Food moves through the digestive system tract by peristalsis, which is produced by wavelike contractions of INVOLUNTARY muscles