Question

I'm having trouble with identifying simple machine.
1)A row boat
2)saw
3)an arm flexing
4)a person hiking
5)a person catching
6)a bikes wheel
Help please!

Answer 1

It's 6, I think, the wheel. Look at all the other ones there: most of them have to do with people, who are most definitely not machines and not simple! A row boat is too big of a thing to be simple, and I don't think it's the saw. That leaves the wheel. Um, look at the note:
Note: this is what I remember from 4th grade science. Don't quote me on it.

Answer 2

http://www.infoplease.com/ce6/sci/A0859409.html

Answer 3

the row boat is simple because it has rows that push the boat using the force of water as a levy to push it. Like a saw is not a machine just a tool, an arm is not a machine, a person hiking is not a machine, person catching is not a machine, wheel can be part of a machine but is not a machine in it's self.