Answer:
composed of ground substance and fibers
Explanation:
The extracellular matrix of connective tissue is composed of ground substance and fibers. In ordinary connective tissue, the ground substance consists mainly of water. The principal fiber type is collagen (the most abundant protein in the body), with elastic fibers as a minor element.
The answer is d) proteins
I am going with x-rays; it is the most visible to the naked eye out of all the choices.
D) Robert Hooke first discovered cells when observing cork under the microscope.