There are some organelles which are found in plant cells but which are not found in the animal cells, these structures will provide a positive identification of a plant cell under a microscope.
The structures which would provide a positive identification of a plant cell under a microscope are CENTRAL VACUOLE, CHLOROPLAST [PLASTIDS] AND CELL WALL. These structures are only present in plant cells.
A string of nucleotides that hold information is called a gene. :)
