表皮
activity
analysis
anatomy
background
biology
botanical
botany
cell
closeup
cross
culture
cut
education
educational
environment
equipment
green
growth
hand
histology
isolated
lab
laboratory
leaf
magnification
membrane
micro
microscope
parenchyma
plant
plant stem
plantation
research
roots
safety
sample
school
science
scientific
section
slice
stem
study
technique
test
tissue
view
wall
xylem