Answer:
One
Explanation:
In a controlled experiment only one variable is changed at a time, while the others are kept the same/controlled so changes can be observed and a causation can be determined.
The correct answer is A) A roast at 125°F (52°C)
Explanation:
In general terms, bacteria thrive at warm temperatures; this means bacterial growth is lower at extremely hot/cold temperatures, but it is higher at warm or medium temperatures. Indeed, the ideal temperature for bacteria to develop and reproduce is between 4° C and 60°C. This implies from the options given the roast at 52°C represents an ideal temperature for the growth of bacteria. Also, other options include temperatures above 60°C, and therefore do not allow bacteria to grow well.
