Photograph by Rich Reid. Tundras are among Earth's coldest, harshest biomes. Tundra ecosystems are treeless regions found in the Arctic and on the tops of mountains, where the climate is cold and windy and rainfall is scant. Tundra lands are snow-covered for much of the year, until summer brings a burst of wildflowers.
Muscle is a soft tissue found in most animals. Muscle cells contain protein filaments of actin and myosin that slide past one another, producing a contraction that changes both the length and the shape of the cell. The statement that the tongue is the strongest muscle in the body appears frequently in lists of surprising facts, but it is difficult to find any definition of strength that would make this statement true. 2  Note that the tongue consists of eight muscles, not one.
Muscular System. The muscular system is composed of more than 600 muscles. These include the involuntary muscles of the heart and the smooth muscles of the internal organs. The skeletal muscles connect to the bones and work with connective tissue at the joints to allow for movement.The muscles connect to the nervous system and allow initiation of movement through nerve signals to and from the brain.he skeletal system and the muscular system work together as the framework for the body as well as providing the pieces that allow for movement.