���spherical objects, irregularly-shaped biological structures, blood vessels/nerve fibers/conduits, cellular components/organelles/subcellular features, viral particles/bacteria/pathogens, connective tissue/blood vessels/nerve fibers, organs (lungs, kidneys, etc.), muscle fibers/fascia/connective tissue, cartilage/cells/tissues, hairs/whiskers/appendages, glands/endocrine organs/accessory glands, bones/cartilage/skeletal structures, arteries/veins/capillaries, tendons/ligaments/fascia/connective tissue, membranes/blood vessels/nervous system components, epithelial cells/tissues/membranes, lymphatic system/components/pathways, nerve fibers/synapses/neurons/cells, sclera/cornea/retina/eye structures