GRE plz help

1. "Observable as a tendency of our culture is a withdrawal of belief in psychoanalysis: we no longer feel it can solve our emotional problems."

What is the grammatical structure of the first clause?

Observable as a tendency of our culture is a withdrawal of belief in psychoanalysis.

I reckon "A tendency" is the subject but what is function of "observable as"? It seems to be a reduced form, plz tell me the full sentence.

2. Ecology, like economics, concerns itself with the movement of valuable…… through a complex network of producers and consumers.

a) commodities

b) nutrients

I chose B but the answer is A.

I think in economics it is the movement of commodities, and correspondingly in ecology, it is nutrients , thus we should fill in the blank B., now we are talking about ecology not economics Why is the answer A?

Thanks