It has been suggested that occupational exposure to benzene in the petroleum industry increases the risk of developing leukemia. the levels of benzene to which workers in this industry have been exposed were high from 1940 to 1970, but since 1970 have been significantly reduced. what kind of study design, using petroleum workers, would provide the most useful information on whether benzene affects incidence rates of leukemia in this industry? you may assume that records of individual worker assignments to jobs involving benzene exposure have been maintained by the industry.

Two police officers stopped a car for a minor traffic violation. while one of the officers dealt with the driver and the traffic violation, the other officer talked with the passenger. seeking to question the passenger about gang involvement, but lacking reasonable suspicions of criminal activity, the officer ordered the passenger out of the car. as the passenger exited the car, the officer saw a bulge in the passenger's coat which the officer suspected might be a gun. upon patting down the passenger, the officer felt the handle of a revolver and removed the gun. the passenger, who was a convicted felon, was charged with the possession of a gun by a prohibited possessor. prior to trial, the defendant sought to suppress the gun as evidence, contending that its seizure was unconstitutional. should the court suppress the gun as evidence? ayes, because, since the car had been stopped for a traffic violation, the officer could not order the passenger, who had not committed the violation, to exit the car. byes, because, since the officer lacked reasonable suspicion that the passenger was engaged in criminal activity, the officer could not pat down the passenger. cno, because a valid traffic stop gives an officer the right to pat down a passenger. dno, because the gun was discovered as a consequence of a valid terry stop and frisk.

On a supply and demand graph, equilibrium is the point where the two curves meet. the supply curve begins. the supply curve ends. the demand curve ends.

Which organelle is marked with an x?