For the answer to the question above, the <span>head circumference is a means of assessing brain growth.
It means that even though her daughter is premature. She's growing normally and without any brain problem or whatsoever and she's healthy.
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The correct answer is option D, difficulty of redesigning workable ecosystems
Reason -
The area that was redesigned into an ecosystem actually failed to attract the endangered species of clapper rails in California because of the following two reasons –
a) Failed attempt of restoration of Cord grass ( a tree which is a dominant tree in the nesting habitat of clapper rail) . Even if few such trees were there they could not grow to their full height and thus were incapable of providing adequate nesting cover
b) Due to the lack of predatory insect, some herbivore insect in the ecosystem attacked the green grasses thereby making the nesting inadequate.
Answer: Independent Variable
Explanation: Already explained this one in another post.