External skeleton is the correct answer. Hope this helps out !
The hypothesis is the question you are trying to answer or the problem you need to figure out, it is kind of like a starting point
I think the answer is D. A good indicator is the resting heart rate. Exercise strengthen your heart and it makes it more efficient. The resting heart rate shows of the heart is pumping blood normally each time it contracts. Having a normal resting heart rate would mean a healthy heart.
This is because direct power has no pulsation (waveform characteristic) that is significant in electromagnetic induction. The gradual increase and decrease of power, at a given frequency, in indirect power is significant in electromagnetic induction. This enables transformers to induce electricity into the secondary coil, from the primary coil, at the core of the transformer.Transformers transform electric power by increasing or decreasing the voltage and current of electricity.