Generally the most senior Senator from the majority party in the Senate, which of the following selections presides over Senate sessions in the absence of the Vice President?

Methamphetamine (meth) is an addictive drug made chiefly in small toxic labs (stls) in homes, tents, barns, or hotel rooms. the manufacturing process is dangerous and often results in explosions, burns, and toxic fumes. government entities spend time and resources to find and destroy stls, imprison meth dealers and users, treat addicts, and provide services for affected families. meth cannot be made without ingredients that are also used in cold and allergy medications. arkansas has one of the highest numbers of stls in the united states. to recoup the costs of fighting the meth epidemic, twenty counties in arkansas filed a suit against pfizer, inc., which makes cold and allergy medications. what is pfizer's ethical responsibility here, and to whom is it owed? why?