Why do we need so many muscles in our hands wrists and arms?

We need so muscles in our hands and wrists because they are the most used or frequently used part of the body. They perform alot of variety of functions like writting and we need to do many things with our hands so they have many muscles and joints.

Hands are delicate structure which make the muscles and joints to perform great movements.

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.