He died and breathed and reproduce
Answer:
The correct answer is option A. "Culture B will have more colonies on the histidine-minus plate than culture A".
Explanation:
In this example, Culture B is a culture of E. coli that has been exposed to a mutagenic agent, therefore it has the potential of developing bacteria that by chance, is able to live in a medium lacking histidine. On the other hand, Culture A is the same E. coli culture but without the exposure to the mutagenic agent. The expected result is that Culture B will have more colonies on the histidine-minus plate than culture A, illustrating that a mutagenic agent can produce E. coli able to reproduce in a histidine-minus plate.
Answer:
It is (x+y)t miles from the school to Bob's home
Explanation:
Assuming the distance from Bob's home to school is d miles and the time taken is t hours
Distance covered when he had flat tire = d/2, time taken = t/2, rate = x miles/hour
Rate = d/t
x = (d/2)/(t/2)
d = xt miles from Bob's home to halfway the school
distance from halfway the school to the school = d/2, time taken = t/2, rate = y miles/hour
rate = d/t
y = (d/2)/(t/2)
d = yt miles
Total distance from school to Bob's home = xt + yt = (x + y)t miles