Background: Unfortunately, the layer of good ozone is being destroyed by air pollution. The chief culprits are chlorine and bromine gases. They are released in aerosol sprays, coolants, and other products. Loss of ozone has created an ozone hole over Antarctica. Ozone depletion results in higher levels of UV radiation reaching Earth. In humans, this increases skin cancers and eye cataracts. It also disturbs the nitrogen cycle, kills plankton, and disrupts ocean food webs. The total loss of the ozone layer would be devastating to most life. Its rate of loss has slowed with restrictions on pollutants, but it is still at risk.

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: At what period would higher level of UV radiation reach earth, time A or time B?
Answer: time B

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: At what period would lower level of UV radiation reach earth, time A or time B?
Answer: time A

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Would level of UV radiation reaching the earth be higher or lower in time A than in time B?
Answer: lower

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Would level of UV radiation reaching the earth be higher or lower in time B than in time A?
Answer: higher

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Would skin cancer be more prevalent or less prevalent in time A than in time B?
Answer: less prevalent

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Would skin cancer be more prevalent or less prevalent in time B than in time A?
Answer: more prevalent

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Which period would see more skin cancer, time A or time B?
Answer: time B

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Which period would see less skin cancer, time A or time B?
Answer: time A

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Which perion would more likely see ocean food webs disrupted, time A or time B?
Answer: time B

Situation: Keith is an environmental scientist. He was studying the loss of ozone layer and its effect on different species. His data showed that in the beginning or twentieth century there were hardly any loss of ozone layer. He categorized that time period as time A. Further inquiry revealed that things didn't go well at the end of twentieth century - when there were severe loss of ozone layer. He categorized that time as time B.

Question: Which perion would less likely see ocean food webs disrupted, time A or time B?
Answer: time A