The main reason why this type of model would be developed is that an animal cell A. is too large to be observed directly
B. is too small to be observed directly
C. moves too quickly to observe directly
D. poses too much risk to observe directly

1. (1.2kw)x(15/60hours) = .3kwh --> a

2. (5kw)x(90/60hours)x(8cents/kwh) = $0.60 --> d

3. microwave --> 1200 watts = (1.2kw)x(6/60hours) = .12kwh

coffee-maker --> 900 watts = (.9kw)x(10/60hours) = .15kwh

therefore, it requires more energy for the coffee-maker to do the same amount of work.

so the answer is a.

i think that is new experiments yield untrustworthy data and should be carefully considered, because you don't know what will happen with the experiments.