Out of the choices provided I would choose B, this is because A is wrong due to simple machines making our work easier and require less energy, C is wrong due to the work actually being done faster due to simple machines. Now D and B felt like they were both correct but D just doesn't make much since when you apply it to the topic of Simple machines so I found B.
Answer: B. A model of a cell is easier to manipulate
Explanation: just took the test//APEX
a) Southward you need to apply right hand rule. If you close your hand to the east, your thumb will indicate south.
b) Given the equation for Magnetic Force

Replacing


c) Given the second Newton's Law by


Given the electric force by,



-- Looking at the dots casually, they look green because they absorb all other
colors of light, and only green light is left to proceed to your eyes. (In order for
this to work, there has to be some green in the light shining on the dots.
Daylight and most light bulbs work fine.)
-- The filter looks red because it absorbs all other colors of light, and only
the red light is left to pass through the filter and come out on the other side.
-- When the green light from the dots hits the red filter, it's absorbed in the
filter, and there's no light left to come out on the other side.
If you're looking through the filter at the dots, they look <em>black</em>.