<span>Positive feedback</span><span>
There are two types of feedback mechanisms
Positive feedback heightens the intensity
Negative feedback lowers the intensity
These all serve to maintain homeostasis. Homeostasis is the state where the internal and external part of the body maintains and establishes balance and equilibrium. </span>
The answer for your question is A.
Probably a hinge joint or a tendon.
The major difference between a light microscope and a electron microscope would be that with the light microscope, a beam of light is used to focus the image. In an electron microscope, a beam of electrons is used to focus the image. Other notable differences would be with the light microscope, your specimens must be very thin; thin enough for light to pass through them. With the EM, you can place whole specimens that can generate 3D images. There is a much more complex specimen preparation process for the EM, where light microscope slide making is fairly simple in comparison. You can view live and wet specimens with a light microscope but you cannot with the EM because an EM requires specimens to be placed in a vacuum chamber. Lastly, the EM is very large and complex to operate, where the light microscope is somewhat portable. Hope this helps!