15.In the 1960's . long-term studies of primate behavior often used as subjects tamarins， small monkeys that were thought ideal because they require only small cages， bread frequently， and grow quickly. Field studies were not used because they were costly and difficult. Tamarins were kept caged in male-female pairs， because otherwise， serious fights erupted between unrelated females. On the basis of the fact that breeding occurred， tamatins were viewed as monogamous.

　　The view taken by the researchers concerning the monogamy of tamarins depended on a questionable assumption.Which of the following could have served as that assumption？

　　（A） The suppression of fighting between related females serves to protect their common genetic inheritance.

　　（B） Adult male tamatins contribute to the care of tamarin infants.

　　（C） The social system of tamarins requires monogamous pairing.

　　（D） Male tamarin monkeys do not display aggressive behavior in the wild.

　　（E） The way the tamarins were kept in cages did not affect their mating behavior.

　　16. Twenty percent of all energy consumed in the United States is consumed by home appliances. If appliances that are twice as energy- efficient as those currently available are produced， this figure will eventually be reduced to about ten percent.The argument above requires which of the following assumptions？

　　（A） Home-appliance usage would not increase along with the energy efficiency of the appliances.

　　（B） It would not be expensive to produce home appliances that are energyefficient.

　　（C） Home-appliance manufacturers now have the technology to produce appliances that are twice as energy-efficient as those currently available.

　　（D） The cost of energy to the consumer world rise with increases in the energy efficiency of home appliances.

　　（E） The percentage of energy consumed by home appliances will increase if existing appliances are not replaced by more energy-efficient models.