Problem: Dan studied two groups of individuals. Group S that had sickle cell anemia, and group B which had normal hemoglobin. He was fascinated by the results. Which group had fewer deformed blood cells?

A: group B

Problem: Two countries are situated on the shores of the same sea. Turkey is a nation of farmers, they use conventional agricultural methods to produce food, including lots of fertilizers. Greece's economy is mostly based on tourism. Which country causes more marine pollution?

A: Turkey

Problem: Two sister cities had different environments. Shanghai had big problems with air pollution while Berna took very good care of the surrounding environment and air quality. Which city had people at increased risk of dying from other diseases?

A: Shanghai

Problem: two countries of similar natural resources had different populations. Italy had a small population, while Spain had a very large population. Which country had a lower reproductive rate?

A:
Spain