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.
Alcohol
may positively affect the cardiovascular system of people over 50 years old by
reducing the risk of clot formation.
<span>Just like with the other body systems, excessive alcohol can have lethal
effects on the cardiovascular system. Chronic alcohol use can upsurge the
workload of the heart which can then lead to arrhythmia's or what is called an irregular
heart beat, inflammation of the heart muscle or myocarditis, weakening of the
heart muscle or cardiomyopathy, increased cholesterol, and even hypertension.
Other problems are prominent with blood clotting and an increased workload of
the heart that is linked to cirrhosis of the liver.</span>
I think A makes the most sense..