Answer:
Cell- the smallest unit of an organism, typically microscopic.
Example: Stem cell, muscle cell, and or bone cell.
Tissue- any of the distinct types of material of which animals or plants are made, consisting of specialized cells and their products.
Example: Connective tissue, epithelial tissue, muscle tissue, and or nervous tissue.
Organ- a part of an organism that is typically self-contained and has a specific vital function, such as the heart or liver in humans.
Example: heart, lungs, liver, eyes, and or stomach.
Organ system- a group of organs that work together as a biological system to perform one or more functions.
Example: Skeletal system, muscular system, circulatory system, respiratory system, digestive system, urinary system, and or immune system.
