There are a few types of muscles. The most "important" (term used very loosely here) are the smooth muscles, they control all bodily functions that are automatic (heartbeat, digestion, ext.) if you were missing any smooth muscle, you could not survive longer than 3 weeks (for digestion) 3 minutes (heartbeat).
The second type, which I am guessing you mean in the question, is skeletal muscles. If you did not have those muscles, life would be possible, but you would be like a sea sponge, food HAS to come to you, reproduction would not be possible in the manner that we are used to (it would need to be either asexual, or like plants).
Without muscle cells we would just lie in a heap on the floor a lot, unable to move.
you would die
Smooth muscles are involuntary in action means muscle that the muscles contract without conscious control. Smooth muscles are found in walls of internal organs such as stomach and intestine and bladder and blood vessels.
Smooth muscles push materials through passageways, remove materials from body parts, make body openings larger and smaller, and contract and restrict tubes in your body.
Smooth Muscle, Cardiac Muscle, and Skeletal Muscle
No, skeletal muscles do, because smooth muscles deal with your internal organs.
There are a number of muscles found in the walls of many internal organs. The common ones include smooth muscles and involuntary muscles among others.
Smooth Muscles can, but Cardiac Muscles can not.
Yes the heart does contract and relax for every moment of ones life .This action enables the blood to circulate the body efficiently
smooth muscles
Arrector pili muscles
Involuntary muscles contract subconsciously.
they both contract and relax to cause movement and both are uninucleated.
CNS
Yes. Smooth muscle can contract cell by cell. This causes muscles to be contracted for very long periods of time.
They are all smooth muscles that contract involuntarily.
Smooth muscles are found in hollow parts of the body. For example they are found in the stomach, intestines, blood vessels, and the bladder. They can contract in all directions.
No, the muscles in your leg are skeletal muscles. Smooth muscle is found for example in vessels and the gastrointistinal tract. Yes smooth muscles are involuntary, which means they contract and relax without our conscious decision for them to do so, however we have control over when we want to move our leg muscles, so it cannot be smooth muscle, they are as said before my answer, quite rightly, skeletal muscles
Smooth Muscle contractions are regulated by calcium ions. The smooth muscle differs from skeletal muscle in that its contracts from all sides.