Question

Researchers conducted an experiment to identify the effects of three different hand sanitizers on the growth of bacteria. The researchers grew one type of bacteria in twenty-four identical covered petri dishes. Then, they opened eighteen petri dishes and applied the three hand sanitizers to six petri dishes each. They left the remaining six petri dishes closed as a control group. When the researchers measured the growth of bacteria two days later, the six dishes that had no hand sanitizer showed the least amount of bacterial growth. The researchers concluded that not using any hand sanitizer would lead to the least bacterial growth.

Which statement best explains why the researchers’ conclusion was not justified?
The experiment tested too many variables.
The control group was not treated the same as the experimental group.
The sample size of twenty-four petri dishes is not large enough.
The single type of bacteria is not adequate to make any conclusions.

Answer 1

Explanation:

the control group was not treated in the same way as experimental group

the control group was left closed while the treated group was left open

this leads to the conclusion that the exposure of the experimental setup to a lot of microorganisms in the air lead to the propagation of bacteria

this is why the scientist's conclusion is not justified

Answer 2

ANSWER:-

• The single type of bacteria is not adequate to make any conclusions is a valid statement which explains why the researchers’ conclusion was not justified.

EXPLANATION:-

• A single type of bacteria is not adequate to make any conclusions, this is because there are numerous kinds of bacteria that are reluctant or immune to multiple different characteristics.
• Probably, the kind of bacteria which was studied has tolerance and susceptibility to hand sanitisers, as we know that the group which was treated with hand sanitisers grew more than the ones that did not have any hand sanitisers in it so it exhibits that the bacteria could be feeding on the hand sanitisers or that they evolved a means to reproduce faster than they would generally reproduce without any sort of pressure from environmental.
• Taking no other conditions into consideration, making conceptions about this particular case would be incorrect then.

#SPJ2