They are genetically and reproductively isolated. For the mule the specific isolation mechanism is termed as "Hybrid Inviability", where the postzygotic isolating mechanism prevents the hybrid from passing on their genes. A zygote may form with the sperm and egg, but the embryo will dies after a few cell divisions. The genetic information from male and female parents is insufficient to carry the organism through morphogenesis. *There are rare documented cases of a mule producing a viable offspring.
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.
This looked familiar to something I’ve done.
I think rotation would be the right answer lol