1
2
3
4
5
200
without tubes or channels
nonvascular
200
probably the oldest living organisms
bacteria
300
too small to be seen with the eye alone
microscopic
300
bacteria cells are different from other cells because they
do not have a nucleus
400
algae and protozoans
protists
400
a living thing
organism
400
non vascular plants lack
tubes for carrying water and food
400
an animal with a backbone
vertibrate
400
having tubes or channels
vascular
500
an animal without a backbone
invertebrate
500
the building blocks of life
cells
500
controls all functions of a cell
nucleus
500
the most numerous organisms on Earth
bacteria
500
Humans are classified into two groups.
vertibrate and mammals
M
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u