Answer:
The correct answer will be option-
18. option-B hypothesis
19. option- A control group
20. option- B experimental group
21. option- C analyzes the data and comes to a conclusion
Step-by-step explanation:
A scientific experiment is a systematic approach to understand and explain the natural events which include various sequential steps.
In question 18, the experiment is conducted to test the well-educated guess based on the background research which explains the phenomenon to a limited extent. This proposed statement is known as the hypothesis and is the answer.
in question 19, the sample group which is left undisturbed or in which the variable to be tested is missing is known as the control group and thus is the correct answer.
in question 20, the sample group in which the independent variable is changed which influence the dependent variable is known as the experimental group.
In question 21, after the experiment, the next step will be the analysis of the collected data from which the conclusion is drawn and is the correct answer.