Why does it make sense for scientists to test just one variable at a time in an experiment

Suppose you are provided with an actively dividing culture of e. coli bacteria to which radioactive thymine has been added. what would happen if a cell replicates once in the presence of this radioactive base?

The hardy-weinberg principle is that genetic frequencies in a population? will remain stable from generation to generation will always be changing will not be affected by environmental changes are always in a 3: 1 ratio

Based on the observations provided, what is the relationship of current diabetes medication use and the use of extract from ginko biloba? a) the anti-inflammatory properties of ginko biloba extract are beneficial in treating t2d separate from the benefits of other therapies. b) the overall abundance of ginko biloba makes this extract an attractive joint therapy for existing medications that are used to treat t2d. c) the side effects of t2d medications have resulted in the need for different therapies to treat t2d like the use of ginko biloba extract. d) clinical outcomes from the use of current t2d medications may be improved through the use of cost-effective ginko biloba extract treatment. e) previous studies with ginko biloba and current t2d medications do not support the use of these treatments as effective against t2d in patients.