The wall of pollen grain is divided into two layers.
A: primary wall and secondary wall
B: pectin layer and primary wall
C: outer wall and inner wall
D: pectin layer and secondary wall
A: primary wall and secondary wall
B: pectin layer and primary wall
C: outer wall and inner wall
D: pectin layer and secondary wall
举一反三
- ( ) is the main layer in cell wall to provide mechanical support. A: Primary wall B: S1 C: S2 D: S3
- One of the differences between the outer wall and the inner wall of pollen is that the outer wall contains the following substances: A: protein B: cellulose C: sporopollenin D: protein and sporopollenin
- The Romans built two walls to keep the picts out of the area they had conquered. The two walls were called ______ and ______. A: the picts’ Wall, Celts’ Wall B: the Hadrian’s Wall, the Antonine Wall C: Britain’s Wall, Scotland’s Wall D: Roman Wall, Julius’ Wall
- Be careful! ________. A: The wall is falling B: The wall is to fall C: he wall will fall D: The wall is going to fall
- Between the outside wall of glass and the two inside walls of glass, there is ______. A: an empty space B: another huge wall C: a triple-glazed wall