Help for 2 GWD CR questions

GWD5-Q21:

In Teruvia, the quantity of rice produced per year is currently just large enough to satisfy domestic demand.  Teruvia’s total rice acreage will not be expanded in the foreseeable future, nor will rice yields per acre increase appreciably.  Teruvia’s population, however, will be increasing significantly for years to come.  Clearly, therefore, Teruvia will soon have to begin importing rice.

Which of the following is an assumption on which the argument depends?

1. No pronounced trend of decreasing per capita demand for rice is imminent in Teruvia.
2. Not all of the acreage in Teruvia currently planted with rice is well suited to the cultivation of rice.
3. None of the strains of rice grown in Teruvia are exceptionally high-yielding.
4. There are no populated regions in Teruvia in which the population will not increase.
5. There are no major crops other than rice for which domestic production and domestic demand are currently in balance in Teruvia.

Why A?

From 1980 to 1989, total consumption of fish in the country of Jurania increased by 4.5 percent, and total consumption of poultry products there increased by 9.0 percent.  During the same period, the population of Jurania increased by 6 percent, in part due to immigration to Jurania from other countries in the region.

If the statements above are true, which of the following must also be true on the basis of them?

1. During the 1980’s in Jurania, profits of wholesale distributors of poultry products increased at a greater rate than did profits of wholesale distributors of fish.

2. For people who immigrated to Jurania during the 1980’s, fish was less likely to be a major part of their diet than was poultry.

3. In 1989 Juranians consumed twice as much poultry as fish.

4. For a significant proportion of Jurania’s population, both fish and poultry products were a regular part of their diet during the 1980’s.

5. Per capita consumption of fish in Jurania was lower in 1989 than in 1980.
                   

I'm not sure about the answer for this one. The key says "E".

GWD5-Q21: population(P) by per capita demand(D) equals total products(TP), PxD=TP,  the argument predicts that   (immigration) increasing will lead to TP(importing) increasing,  therefore, the assumption is that D will not decrease. so A) is the right answer.

I gree with you that key for  GWD-4-8 is E