Select the correct answer. Prolonged and constant use of tobacco can weaken the user's immune system and increase the risk of many diseases.
Which disease makes the air sacs in the lungs less elastic, reducing their ability to absorb oxygen?
OA
chronic bronchitis
O B.
emphysema
O C.
lung cancer
O D. oral cancer

which ever one is showing doing the same exercise in time intervals such as 30 seconds or a minute several times.

no, because those are both different running competitions. while distance runners train their legs and their lungs to run long amounts of time, the sprinters are training their legs and their lungs to give all they have in the little amount of area they need to cover. the brain also plays a huge part in all of this.

the brain is the only thing in your body that sends messages to your body telling you to run. if you are a long distance runner and you have the mind set of a sprinter, you will not get anywhere. if you have a long distance mind set and you have to run 200m in 20 seconds then you will not make it in time.