Problem: Two friends met after 20 years. Tom had been smoking tobacco all these years and had some health problems related to that, while Randy quit smoking 25 years ago. Which friend had an increased risk of developing cancer of the lung?

A: Tom

Problem: John was a relatively thin and bone-y child when he was younger. He would often get bruises and was prone to breaking bones. As an adult however he does lots of weight lifting and hasn't broken a bone yet. Will lifting weights likely increase or decrease bone thickness?

A: increase

Problem: Scientists studied two groups of plants. Group F had plants with flowers, group W had plants that fertilize over wind- spread pollen. Flowering plants were more efficient. Which group of plants has a lower fertilization efficiency?

A: group W

Problem: Two twin sisters, Bianca and Rosa, were exposed to high levels of air pollution. While Bianca was exposed mostly to indoor pollution, Rosa was heavily exposed to outdoor pollution. Which sister got more fresh air?

A:
Rosa