Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

[Q]: Precursor cells have been shown to be affected by oxidative stress, in vivo and vitro, but little is known about the expression of antioxidant mechanisms in neuronal/glial differentiation. We have characterized the expression of Cu/Zn superoxide dismutase (Cu/Zn SOD), one of the main antioxidant proteins involved in the breakdown of superoxide, in the immature rat dorsolateral subventricular zone (SVZ), rostral migratory stream (RMS) and hippocampal subgranular zone (SGZ). Progenitor cells were identified immunohistochemically on cryostat sections by 5'Bromodeoxyuridine (BrdU) incorporation and expressing cells were further characterized using double labeling for progenitor markers. In the SVZ, only a subpopulation of BrdU+ cells, mostly found in the medial SVZ, expressed Cu/Zn SOD. These cells were mostly nestin+ and some were also vimentin+. In contrast, in the lateral SVZ few Cu/Zn SOD+/BrdU+ cells were found. These were primarily nestin+, vimentin-, showed some PSA-NCAM expression, but only a few were NG2+. In the RMS and SGZ virtually all BrdU+ progenitors were Cu/Zn SOD+ and expressed nestin and vimentin. Some RMS cells were also PSA-NCAM+. These findings show a heterogeneous expression of Cu/Zn SOD in restricted cell types in the germinative zones and suggest a role for antioxidant Cu/Zn SOD in progenitor cells of the immature rat brain.
[A]: Which intermediate filament (IF) protein can be used as a non-specific marker of the neuronal precursor cells of the subventricular zone?


[Q]: The Van Gogh Museum's Wheatfield with Crows was painted in July 1890, in the last weeks of van Gogh's life.
[A]: What is the name of the place where Wheatfield with Crows can be found?


[Q]: Australia is the smallest continent in the world. It is a little smaller than China. It is on the Southern Hemisphere of the earth. Australia is big, but its population is small. The population of Australia is nearly as large as that of Shanghai. Enough laws have been made to fight against pollution. The cities in Australia have little air or water pollution. The sky is blue and the water is clean. You can clearly see fish in the rivers. Plants grow very well. Last month we visited Perth, the biggest city in Western Australia, and went to a wild flower _ . There we saw large numbers of wild flowers on show, most of which we had never seen before. We had a wonderful time. Perth is famous for its beautiful wild flowers. Every year in spring Perth has wild flower exhibitions. After visiting Perth, we spent a day in the countryside. We sat down and had a rest near a path at the foot of a hill. It was quiet and we enjoyed ourselves very much. When we heard bells ringing at the top of the hill, we looked up, but what we saw made us pick up all our things and run back to our car as quickly as we could. There were about three hundred sheep coming towards us along the path. Australia is famous for its sheep and kangaroos . After a short drive from any town, you will find yourself among the white sheep. Sheep, sheep, everywhere you can see sheep.
[A]:
Which country is the writer most possibly from?