These nematodes, sold under the names of Scanmask and Nemasys, are microscopic, wormlike creatures that will destroy the fungus gnats but are not harmful to people, pets, plants, or earthworms. These products can be used whenever the soil is not frozen and will keep working for many months.
Vegetative structures. There are three levels of integrated organization in the vegetative plant body: organ, tissue system, and tissue. The organs of the plantâthe roots, stems, and leavesâare composed of tissue systems (dermal tissue, ground tissue, and vascular tissue; see below Tissue systems).
Background. 1  Composed of cells, tissues, organs, organ systems. 2  All cells use ATP for reactions. 3  Four primary types of tissue: epithelial, connective, muscle, and nervous.  Organs have at least two or more types of 1  tissue. Organ systems: