Which of the following causes the change in seasons on Earth?
A. the Earth revolving around the Sun, and the moon revolving around the Earth
B. the spinning of the Earth on its axis, and the Earth revolving around the Sun
C. the tilting of the Earth on its axis, and the sun revolving around the Earth
D. the tilting of the Earth on its axis, and the Earth revolving around the Sun

D.the tilting of the Earth on its axis, and the Earth revolving around the Sun

Explanation:

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.