Answer:
do u just need definitions?
Explanation:
The first time a pathogen hits, our bodies do not know how to handle it properly. This means that our bodies take more time to handle it the first time around. The second time around, however, our bodies have altered so that they can handle the pathogen more efficiently. Hope this helps!
The answer is letter A.
Biking or bicycling is a form aerobic exercise that develops cardiorespiratory fitness. This is because the heart and lungs are the important organs that function when this activity is being done. Biking for 30 minutes to more than a few hours will inhibit the strengthening of the muscles of the heart and the ability of the lungs to convert unoxygenated blood into oxygenated blood. If you engage in this activity on a regular basis, you will notice and improvement in your performance.
Melatonin is responsible for sleep and wake pattern known as the circadian rhythm.
