Background: Many chemicals that were once commonly used were later found out to be harmful to the environment , to human health, or both. The element lead was once a common additive to gasoline and to paint. Plumbing pipes were once typically made of lead. Only since the 1970s has the danger of lead become apparent. It causes brain damage and small children (who often chewed on objects painted with lead-based paint) are particularly susceptible. The use of lead in gasoline, paint, and plumbing pipes is now banned and new materials are being developed to replace the hazardous lead components.

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied more about lead?
Answer: Tim

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied less about lead?
Answer: Jeb

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied less about what causes brain damage in children?
Answer: Jeb

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied more about what causes brain damage in children?
Answer: Tim

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied less about the use of lead?
Answer: Jeb

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied more about the use of lead?
Answer: Tim

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied more about gasoline?
Answer: Tim

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied less about gasoline?
Answer: Jeb

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied less about paint?
Answer: Jeb

Situation: Tim and Jeb were both studying chemical engineering. At a certain point in time, Jeb started studying chemicals that are not harmful for the environment, while Tim started learning about chemicals that were once used, but now are known to be harmful for the environment.

Question: Which student studied more about paint?
Answer: Tim