As you have probably guessed, the main function of the muscular system is movement, but it also helps stabilize our joints, maintain our posture and generate heat during activity. Movement of our body can be voluntary and controlled by the skeletal muscles, or it can be involuntary and controlled by smooth muscles.
Answer: Valves in the veins
Explanation: The flow of the blood inside the body takes place through the veins and arteries. The oxygenated blood from the heart is supplied to the different parts of the body.
The blood flows from the capillaries to the venules and from there to the veins. The blood moves in the veins by the rhythmic movement of the smooth muscles in the body.
Most of the blood moves against the gravity so there is a chance that it can backflow so to prevent this there are valves in the veins known as one way valves.
Its either A or C. thats all i can say though but B and D you can rule out. I hope i helped a little
Answer:
Earth's upper atmosphere controls the radiation that escapes to space.
(please give brainliest)
Although now it causes more harm than good because it doesn't really have a purpose, it is believed it once was used for humans to digest bone.
