单项选择题

Questions 19-20 are based on the following passage.
A recent assessment of the status of global
amphibian populations identified habitat
loss as the single greatest identifiable factor
Line contributing to amphibian declines. Habitat
(5) loss primarily results from the residential,
agricultural, arboricultural, or recreational
development of an area.
Anthropogenic conversion of land has
caused significant reductions in the wetland,
(10) forest, and grassland habitat that amphibians
require for their survival. Outright habitat
loss probably has the greatest effect on
amphibians, but habitat degradation, or the
general decline in the health of a habitat,
(15) often results from environmental contamina-
tion, the introduction of exotic invasive
species, or a reduction in required resources
within a habitat, and similarly affects
amphibians. Likewise, habitat fragmentation
(20) (the disruption or fragmentation of habitat
into discontinuous or isolated remnants of
viable habitat) emerges from isolated patches
of habitat loss and can often have delayed
effects on animal populations.
Directions: For the following question, consider each of the choices separately and select all that apply. In the course of the passage, the author does all of the following EXCEPT