The theory that the impact of a giant meteorite caused the extinction of the dinosaurs is based on evidence that a cloud of dust from the impact blocked off sunlight around the globe for months, reducing temperatures and destroying the dinosaurs food supply. Which of the following, if true, casts the most serious doubt on the theory above?
A.Dinosaurs are believed to have been cold-blooded and thus very sensitive to any temperature change.
B.Some dinosaurs lived in regions where their food supply was not well adapted for long periods of cold and darkness.
C.Many large animals that existed during the time of the dinosaurs and shared a common food supply with them continued to populate the Earth long after the extinction of the dinosaurs.
D.A large volcanic explosion that strewed dust in the air and blocked out sunlight was the cause of death of animals within hundreds of miles of the eruption.
E.Many of the largest dinosaurs were herbivorous relying exclusively on vegetation for their dietary needs.
Until recently experts believed that environment, not genetics, largely determines human personality. A new study, however, has shown that there is more similarity in personality between identical twins raised together than between non-identical twins raised together. The study concluded that genetics, therefore, does play an important role in determining personality. Which of the following, if found to be true, would cast the most doubt on the studys conclusion?
A.Identical twins raised separately in different adoptive families are usually more similar in personality than are nonidentical twins raised separately in different adoptive families.
B.No matter how twins behave, parents treat identical twins in ways that tend to elicit similar personality traits but do not treat nonidentical twins in such ways.
C.Parents of both identical and nonidentical twins have long claimed that their children, from early infanthood, had definite and well-established personality traits.
D.Birth parents and their identical twin children tend to become more similar to each other in personality over time, but adoptive parents and their identical twin children do not.
E.Neither identical nor nonidentical twins are likely to display drastic changes in their individual personalities as they grow up.
The major goal of physical education programs in schools is to help all children become physically fit. But only a small proportion of children ever participate in team sports. Moreover, team sports usually do less to encourage fitness in participants than do physical education programs that focus directly on aerobic exercise. The considerations above, if true, could be used most effectively to argue against
A.the use of in-school physical education programs to encourage lifelong fitness habits in students.
B.the participation by young children in community sports teams.
C.schools" relying heavily on aerobic exercise programs to help all children become physically fit.
D.the use of a large part of a school" s physical education curriculum for team sports.
E.the use of team sports in schools as an occasional activity for talented athletes.