Ascientist wishes to determine the effect of a digestive enzyme on starch digestion (starch is broken down into glucose). the experimental setup is to mix the enzyme with starch in a test tube, stop the reaction after a known period of time, and then measure the amount of glucose produced.

which of the following is the correct experimental control?

An identical setup but replacing the enzyme with an equal volume of water

Explanation:

When carrying out any experiment, it is important to set out a control in order to increase the reliability of the data and results.

The control minimizes the effects of variables other than the independent variable.

In the above experiment, starch has to be eliminated and replaced with water. Water does not have starch hence the digestive enzyme being tested will not have any effects making the data and results from the experimental group reliable.

americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.

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