C. A flow of matter from one point to another.
Every one has a reason in life. You may not know what it is just yet, but you do.
C. Electromagnetic waves don't always need a medium to travel. Note that they do vary in wavelength and frequency however their speed is fixed. Also, EM waves are always transverse and they consist of vibrating electric and magnetic fields.
An inclined plane has less of a mechanical advantage because it has to have more work to take so,etching up than down. I hope this makes sense.
