14.There are 156 known species of glass frogs living throughout the neotropics.Recent advancements in genetics are giving researchers a revealing look into the lives of these one-inch-long tree dwellers,some of which are the size of a paper clip.
Scientists have discovered,for example,that male glass frogs in some species are
stellar parents-a rare trait among vertebrates (脊椎動(dòng)物).Males of at least 24 species not only protect their eggs from predators but also actively care for them.While the embryos(胚胎) develop,males of some species,such as the sun glass frog sit atop their egg clutch "like a chicken,"keeping the eggs hydrated until they hatch into tadpoles(蝌蚪).
New research is also discovering how the glass frog's transparent belly forms.It's suspected that young glass frogs physically rearrange the insides of their cells and tissues to become transparent adults.Fluid between the tissue cells may also contain a substance that allows light to travel through.
Another mechanism that may allow glass frogs to blend into the green leaves on which they doze during the day is called "a biological mirror",a kind of shield or covering of crystals in many of their tissues,which reflects up to 30 percent of the light that normally reaches them.Those crystals amplify the light signal,and the frog's green looks brighter.
Many scientists studying glass frogs arc motivated by the fact that some of their subjects are disappearing-and fast.Agriculture,cattle grazing,and mining projects in the Andes are taking over the frogs' already fractured forest homes.
"As soon as they are discovered,many species are declared endangered," Guayasamin,a biologist in Ecuador,says "yet there could be an advantage in conserving such isolated ponulanons." All could be inspired to work together to set aside frog-rich patches of land as reserves,ensuring that these delicate creatures have a solid chance at survival.
(1)What can we know about glass frogs?
A.They are regarded dangerous.
B.They are small animals.
C.They are of different colors.
D.They live in the water.
(2)What does the underlined word "stellar" in paragraph 2 probably mean?
A.Strange.
B.Ambitious.
C.Excellent.
D.Different.
(3)How can glass frogs hide themselves in the green leaves?
A.They physically change their cells.
B.They contain transparent fluid.
C.Crystals in their tissues reflect light.
D.Light signal makes them greener.
(4)What is Guayasamin's suggestion for endangered glass frogs?
A.Stopping cattle grazing.
B.Building frog reserves.
C.Improving frog popularity.
D.Planting more forest trees.