The two principal types of connective tissue in a
muscle are collagen and myofibrils. The entire muscle is wrapped in collagen to
form a fascicle. Looking at one muscle fiber, you will see that almost the
entire cross section of the muscle fiber is composed of long, cylindrical
strands of proteins called myofibrils<span>. </span>
Cells divide in an effort to reproduce and create more of themselves to keep their larger- encompassing species sustained.
Answer:
The populations become adapted to different environments and eventually become so different that they cannot interbreed to produce fertile offspring.
Speciation is the evolution of one species into two different kinds, and when they become isolated, that is the final step, since they cannot interbreed any longer.
