Answer:
B
Explanation:
B is the best answer it explain alot
A. Microorganisms can have both positive and negative effects on other organisms
You have no obligation because its none of your buisness
A Muscle Contraction Is Triggered When an Action Potential Travels Along the Nerves to the Muscles. Muscle contraction begins when the nervous system generates a signal. The signal, an impulse called an action potential, travels through a type of nerve cell called a motor neuron.
One it can effect your lungs
two your mind and how you thinking
three your physical health
four your life spand
