Explain how you found out that Lucy has ADA-SCID

The first part in finding out Lucy has ADA-SCID was when I realized there was no HIV proteins in her blood, which got rid of the possibility of her having HIV. Then, I saw that she had a high number of Deoxyadenosine in her blood. This proves to me that she has ADA-SCID because when the ADA doesn't work you find excess amounts of Deoxyadenosine in the blood. This is the answer.

Explanation:

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.

instead of copying and pasting things off of tests or work done on computer which im sure you did, try and read over the question carefully