The true descriptions regarding muscles are; Cardiac muscles and skeletal muscles are striated, heart (cardiac) and digestive (smooth) muscles are involuntary muscles, cardiac muscles work to pump blood. Skeletal muscles are the muscles that attach to the bones and their main function i contracting to facilitate movement of our skeletons. Smooth muscle are found in walls of hollow organs such as the stomach and are stimulated by involuntary action. While the cardiac muscles are found solely in the walls of the heart, they are highly specialized and under the control of of the autonomic nervous system.
The hormone calcitonin, which is produced by the parafollicular or C cells of the thyroid, has the opposite effect on blood calcium levels as does PTH. I hope this helps! : )
Answer:
Although you normally hear about trying to reduce or eliminate friction, it actually has some important uses.
Since friction is a resistance force that slows down or prevents motion, it is necessary in many applications where you might want to hold items or do things and prevent slipping or sliding. In those cases, there is an advantage of having friction.
Quite often uses of frction can be seen from how things would be without friction. Without friction, you would not be able to walk, drive a car, or hold objects. Pens and pencils would not work.
Explanation:
A theory that states that only the organism with traits that are useful to the environment survive. For example, short-neck giraffes would’ve died out years ago as they can’t reach the trees nor eat grass on the ground.
