Part a)
per day electricity power consumed when 100 W bulb is used for 8 hours

for one year consumption

now the cost will be given

now when other energy efficient light is used

for one year consumption

now the cost will be given

Brain-powered cars?
The answer would be people who lack motor skills in their legs.
<span>The question is asking how many moons Venus, the planet, has and the answer is 0 -Venus doesn't have any moons. Another planet that doesn't have any moons is Mercury. Earth has one moon and Mars has two moons. Jupiter has 4 moons and the most impressive is Saturn, with its 53 confirmed moons (as claimed by Nasa)!</span>