A is the answer. If something's a single cell organism, then they're prokaryotic
Answer:
There are no options in the question but mitochondria is the power house of the cell while nerve cells transmit or send impulses or information from one place to another in the body.
It's natural and human caused.
I don't really know but I hope it helped.
Answer: Skeletal Muscles
Explanation:
Skeletal muscle is one of the three muscles that is found in the body. Other two types are cardiac and smooth mucles.
It is formed by the striated tissues that are under the voluntary control of the somatic nervous system.
They are attached to the boned by the bundles of collagen fibers. The muscles consists of actin and myosin whose repeated units are known as sarcomere.
This sarcomere provides this muscle the striated appearance.