Your question is badly written. unless you're looking for the avagrados number than its 6 x 10^23 and it means that for every one mole there that number.
If I'm not mistaken id say its small temperature changes
The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in the walls of the heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow visceral organs, except the heart, appear spindle-shaped, and are also under involuntary control. Skeletal muscle fibers occur in muscles which are attached to the skeleton. They are striated in appearance and are under voluntary control.
Answer:
Due to adaptation and evolution, the giraffes' neck has evolved to be extremely long. As we know, giraffe's tend to eat leaves from higher up branches in the trees. Since few mamals are able to reach up that high, they have more food.
To put it simply, a giraffe's neck has evolved to be so long due to their food choices.