The main organ of the respiratory system is the lungs.
Answer:
bone density.
Explanation:
I used precess of elimination. U cannot improve the bone density by working out. You can improve your cardiorespiratory fitness by doing cardio, e.g. cycling, swimming, running etc. You can improve muscular strength by working out, e.g. push up, sit ups, etc. you can also become more.flexible by expanding ur muscles and tissues.
Answer:
Addiction.
Explanation:
A person with an addiction uses a substance, or engages in a behavior, for which the rewarding effects provide a compelling incentive to repeat the activity, despite detrimental consequences. Addiction may involve the use of substances such as alcohol, inhalants, opioids, cocaine, and nicotine, or behaviors such as gambling.
There is evidence that addictive behaviors share key neurobiological features: They intensely involve brain pathways of reward and reinforcement, which involve the neurotransmitter dopamine. And, in keeping with other highly motivated states, they lead to the pruning of synapses in the prefrontal cortex, home of the brain's highest functions, so that attention is highly focused on cues related to the target substance or activity. It is important to know that such brain changes are reversible after the substance use or behavior is discontinued
