Answer: The NEGATIVE CONTROl is the test tube that is filled with ONLY distilled water.
Explanation:
A negative control of an experiment is carried out alongside the main primary experiment except that the treatment is changed to something that is predicted to have no result. In the negative control, the student does not expect any response. This would help the student compare the result of a new experiment against an already known existing results.
Analysing the experiment carried out by the student, She filled two test tubes with distilled water and placed a piece of Elodea in one of the tubes, leaving the other without a plant. The other test tube that contains only distilled water is the negative control because she wasn't expecting any result from it. It's also served as a control sample to the primary experiment. This is observed as she blew in each tube to add carbon dioxide, which caused the distilled water to become more acidic. This would help the student know that the that experimental results are valid and to ensure that time is saved.
Answer:Entre un bioma y otro no hay un limite sino una gradación progresiva, y aunque en la actualidad todavía no se ha llegado a un acuerdo exacto sobre el numero de biomas.
Explanation:
<span>The answer is D. The living things in a biological community are called biotic components. Living things incorporate plants, creatures, microscopic organisms, parasites and that's only the tip of the iceberg. The non living parts of an environment are called abiotic elements. In a biological community some abiotic variables are daylight, temperature environmental gasses water and soil.</span>
Answer: The answer is the rental system.
Explanation: It produces, stores and eliminates urine and the fluid waste excreted by the kidneys.