a) is an aquatic grass with thin, flat, elongated leaves
b) is adapted to fast-flowing water of high quality
c) is killed by silting or disturbance of the river bottom
d) is found only in the upper four miles of the San Marcos River
e) all of the above

4.

The endangered Fountain Darter:

a) feeds primarily in daylight on aquatic insect larvae
b) prefers moving prey
c) prefers clear, quiet backwaters
d) is found only in the San Marcos and Comal rivers
e) all of the above

5.

The endangered Comal Springs Riffle Beetle:

a) lives in the gravel substrate and shallow riffles in spring runs
b) grows to about 1/8 inch long, with females slightly larger
c) is incapable of flight, unlike other riffle beetles
d) is found only in San Marcos and Comal Springs
e) all of the above

6.

The endangered Comal Springs Dryopid Beetle:

a) is subterranean, with vestigial eyes
b) is weakly pigmented, translucent, and thin-skinned
c) is assumed to live in air-filled voids inside spring orifices
d) was first described as a new species in 1992
e) all of the above

7.

The endangered Peck's Cave Amphipod:

a) is a subterranean, aquatic crustacean
b) is eyeless and unpigmented
c) have mostly been found in crevices in rock and gravel
d) is not named after a particular cave
e) all of the above

8.

The endangered Texas Blind Salamander:

a) spends its entire life in complete darkness
b) reaches a length of about five inches
c) is very sensitive to changes in water quality
d) is a carnivorous predator
e) all of the above

9.

Ecologically, cave invertebrates can be described as more similar to large mammals like elephants than to their invertebrate cousins which live on the surface. Like elephants, they have few offspring and live relatively long lives, a characteristic ecologists call "K-selected". This also means their populations are more sensitive to losing even fairly small numbers of individuals, and that it takes a long time for their population sizes to recover from any catastrophe.

a) true
b) false

10.

The endangered Helotes mold beetle:

a) is a tiny, reddish-brown beetle up to 2.4 mm in length
b) resembles an ant
c) is known to inhabit eight caves near Helotes
d) has only been collected three times
e) all of the above