Test knowledge: The right choice of words/ Compound adjectives
One of the ways to form compound adjectives is to apply the formula “Adverb + P2”, in this case, the adverb is well.
The options are explained as follows:
A. (well) arranged (adj): well arranged.
B. (well) organized (adj): well organized
C. (well) established (adj): to stand firm, to last for a long time
D. (well) acquired (adj): well absorbed (talking about knowledge, skills)
When combined with the subject “The connection”, option C is the most suitable.
Sentence meaning : The link between sleep deprivation, memory loss, slow reaction levels, and poor concentration has been known for a long time.