One difference between algae and plants is that plants have roots, stems, or leaves plants conduct photosynthesis plants are multicellular

The answer is:  [A]:  "plants have roots, stems, or leaves" .

Note that BOTH algae AND plants:

  1)  conduct photosynthesis (that is, many algae do; and many "true plants" do; and: 

  2)  are multicellular — plants are multicellular; and many are multicellular (though some algae are unicellular, as well).

Ithink the answer is true