Compared to bacteria cells, viruses are

Viruses have to invade the body of a host organism in order to replicate their particles. Therefore, most viruses are pathogenic. The main difference between bacteria and virus is that bacteria are living cells, reproducing independently and viruses are nonliving particles, requiring a host cell for their replication.

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when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.