Answer:
What is the universe made of? Astronomers face an embarrassing conundrum: they don't know what 95% of the universe is made of.
Explanation:
I need more information to answer the question
They help to prevent the disease from occurring. The immune system becomes familiar with the pathogen and learns how to fight it. Its the same process with vaccines
Answer:
The answer is B: All the muscle cells innervated by a single motor neurorn.
Explanation:
It is called a motor unit, all muscle fibers that are innervated by a motor neuron cell. A motor neuron cell can establish contact with up to 150 muscle fibrils, which when activated causes their simultaneous contraction, therefore, all the muscle fibers of a motor unit contract and relax at the same time.
