What is double fertilization in angiosperms?
A. One sperm fuses the egg cell
B. Another sperm fuses the central cell
C. One sperm fuses the synergid
D. Another sperm fuses the antipodal cell
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When animals transmit seeds, it is generally necessary to have _______or _________structures on the surface of fruits to be carried easily
A. smooth
B. barb-shaped
C. spine-shaped
D. wing-shaped
The woody parts developed by plants from ___________to___________ every year are called annual rings.
A. Spring
B. winter
C. Summer
D. Autumn
What are the traits of vegetative organ metamorphosis of plants?
A. Morphological changes
B. Can be inherited
C. Physiological changes
D. Can not be inherited
Which season woods developed by plants collectively known as annual rings ?
A. Spring
B. winter
C. Summer
D. Autumn