An exchange reaction occurs between compounds that, when written as a molecular equation, appear to involve the exchange of parts between the two reactants. An exchange reaction will occur when ions in solution form insoluble products, weak electrolytes, or non electrolytes.
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.
The immigration rate and the emigration rate are equal in case of a stable population.
Option A
<h3><u>Explanation:</u></h3>
A stable population is defined as the number of individuals residing in an environment with a limited resources and the number of individuals residing more or less remains constant. In case of a population, there are different factors which tends to divert the population out of the stability, like immigration or emigration. Immigration is the addition of individuals to the population from outside which increases the population, and emigration is the loss of individuals which decrease the population. In case of a stable population, the number of immigrants and emigrants remain more or less same, which maintains a stable population.
If 100,000 kJ of energy is available to the producers, 1000 energy is available to the secondary consumers in this food pyramid.
<h3>What is 10 law of energy flow explain?</h3>
According to ten per cent law only 10 per cent of the energy entering a certain trophic level of organisms is known for transfer to the next higher trophic level.
Thus, 1000 energy is available to the secondary consumers in this food pyramid.
To learn more about energy transfer click here:
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Answer:
8. A
Explanation:
they are moved by strong, steady winds called unidirectional winds, which move from the south west to the north east
