LEVITY:（）

A．searching for an accurate method of determining whether the universe is finite or infinite
B．discussing problems and possibilities involved in providing a definite picture of the shape of the universe
C．declaring opposition to the notion that spherical geometry is a possible model for the shape of the universe
D．criticizing discredited theories about the possible topologies of the universe
E．refuting the idea that there is no way to tell whether the universe is finite and if so what shape it has

A．Of the three models of spatial curvature proposed by Einstein, only spherical geometry contradicts the Euclidean model.
B．The primary evidence for the notion is that that observers cannot see spatial flexure directly, but perceive it as gravitational attraction.
C．Space mapped on the spherical geometrical model may curve in one of three ways, as Einstein proposed.
D．Spheres typically contain only three dimensions, whereas most models of the universe attribute it at least four.
E．Scientists are skeptical, given that mass and energy quantities seem insufficient, yet ultimately do not know enough to dismiss the notion.

A．The second paragraph limits the applicability of the theoretical method described in the first paragraph.
B．The second paragraph provides further elaboration on why an assertion made at the end of the first paragraph proves true in most cases.
C．The second paragraph provides additional information in support of a hypothesis stated in the first paragraph.
D．The second paragraph provides an example of a case in which the assumption described in the first paragraph is warranted.
E．The second paragraph describes a phenomenon that has the same cause as the phenomenon described in the first paragraph.