Yea you could also look at the sample student answers on bos standard packages for physics just to get an idea of whats to be expected, but for "Expain the differences between electromagnetic waves and mechanical waves" your answer should include:
Mechanical waves - require medium, propagate by transferring energy by oscillating particles, and travel much slower than electromagnetic waves.
Electromagnetic waves - do not require medium, can travel through vacuum, self propagate through alternating electric and magnetic fields, travel at speed of light.