either they are unicellular, or they are multicellular without specialized tissues.
The chlorophyta and rhodophtya multicelled seaweed of the oceans.
Both Rhodophyta and Chlorophyta are plant like protists. Instead of roots they have holdfasts. Instead of stems they have stapes. Instead of leaves they have blades. Often called seaweed, but they are multicelled protists. Google them
They are all multicellular and heterotrophic, but do not have cell walls.
Humans for one. Its the term for multicelled creatures. Most living organisms, including all animals, plants, fungi, and protists, are eukaryotes.
Generally they are, but some plant like protists such as Rhodophyta and Chlorophyta are large multicelled protist seaweeds that closely resemble plants. Instead of roots they have holdfasts that anchor them to the sea floor, instead of stems they have stipes and instead of leaves they have blades that hold chloroplasts for photosynthetic purposes.
Google Rhodophyta and Chlorophyta to read about these multicelled plant like protists. A hold fast instead of roots, a stipe instead of stems and blades instead of leaves, but still an autotroph.
yes
yes
What is used to provide support in plants for cells in multicelled organisms
invertabrate
multicelled
multicelled