Question

scientific fact, sadly, it is just a myth.
scientists from clemson university in south carolina tested the five - second rule in 2007. first, they covered three different floor surfaces with salmonella bacteria. salmonella, which is often found on raw chicken, is a major cause of food poisoning. after coating the floors in salmonella, they dropped bologna sandwiches on these contaminated surfaces. finally, they measured the amount of bacteria on the food.
the scientists discovered that food that had been on the floor for just five seconds could have up to 8,000 bacteria on it. food that was left for one minute had ten times that amount—up to 80,000 bacteria. because you can get food poisoning from as few as ten salmonella bacteria, even a small amount of salmonella can be dangerous. this means that the five - second rule is simply not true.
in addition to the amount of time food has spent on the floor, the location of the floor itself also plays an important part in how many bacteria may be transferred to your food. surprisingly, many outdoor locations are actually cleaner than some places inside your house! according to dr. harley rotbart, a professor at the university of colorado school of medicine, the sidewalk is likely to be cleaner than your kitchen floor. rotbart argues that the germs from raw meats that are probably in your kitchen are far more dangerous than the bacteria typically found on pavement. unsurprisingly, the bathroom floor is also likely to have more dangerous bacteria on it than the sidewalk.
the type of food you have dropped can also affect the number of bacteria on the food. foods that are high in salt or sugar but low in water content—like cookies or crackers—grow fewer bacteria. so, after they have come into contact with the floor, food with a higher water content, such as cooked pasta or sliced fruit, picks up a larger quantity of bacteria.
so, what does this mean for your dropped chocolate chip cookie? if you dropped it outside on the sidewalk, the five - second rule might keep you safe. however, if you dropped it...
challenge question
according to the passage, the amount of bacteria on dropped food depends on
i. where the food has been dropped
ii. what kind of food has been dropped
iii. how long the food has been on the floor
a i and ii only
b i and iii only
c ii and iii only
d i, ii, and iii

Explanation:

To solve this, we analyze each factor:

• I. Where the food has been dropped: The passage states that location (e.g., sidewalk vs. kitchen floor, outdoor vs. indoor) affects bacteria transfer, so this is a factor.
• II. What kind of food has been dropped: It mentions that food type (e.g., high salt/sugar vs. low water content, cooked vs. raw) affects bacteria amount, so this is a factor.
• III. How long the food has been on the floor: The "five - second rule" is debunked, and time (even a small amount) matters for bacteria transfer, so this is a factor.

Since all three (I, II, III) are factors, we check the options. Option D includes all three.

Answer:

D. I, II, and III