Changing only one variable at a time is a rule for conducting a controlled
experiment.
Controlled experiment involves the use of dependent and independent
variables . Changes in the independent variable brings about a
corresponding change in the dependent variable which is then recorded.
It is however important to note that changing more than only one variable at
a time won't accurately determine if the changes in the results were as a
result of one cause. This is why only one variable has to be changed at a
time.
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The answer is D yayayayay
<span>Reptiles that live on land convert the ammonia in their unrine to uric acid, which is much less toxic , so it doesn't need to be diluted as much. Also excess water is absorbed in the cloaca, reducing the urine to a paste and conserving water.</span>