脂肪吸收的途径是
A. 血液
B. 淋巴
C. 组织液
D. 脑脊液
E. 以上都不对
Mammals breathe with ____.
A. lungs
B. gills(鳃)
C. wings
D. eggs
The process that takes place as a tadpole (蝌蚪) changes into a frog is ____.
A. digestion (消化)
B. metamorphosis (变形)
C. photosynthesis (光合作用)
D. protection
____ is the only mammal capable of true flight.
A. The bald eagle
B. The flying squirrel
C. The bat
D. The penguin