If jorge is<span> feeling sluggish and having trouble concentrating in class, he should (option A) go to sleep earlier. So he could have enough amount of time to sleep (between 8 and 9 hours depending on each person), his brain and body would rest properly and he is going to feel better in the morning. If he does this every day and respect his night sleep, he won´t have any of these problems in the future. </span>
Your answer would be the Kidney
The kidney was the first organ to have an artificial replacement; the dialysis machine invented by Kolff in the 1940s.
