1. Cells-The cell is the basic unit of structure and function of a living thing.
Cells are specialized by size and shape for the job they do. Multicellular organisms contain a vast array of highly specialized cells. Plants contain root cells, leaf cells, and stem cells. Humans have skin cells, nerve cells, and sex cells. Each kind of cell is structured to perform a highly specialized function. Often, examining a cell's structure reveals much about its function in the organismexample:2. Tissues-Tissues are made of a group of similar cells that work together to do a specific job in the body.Examples: 4 different types of animal tissues are epithelial, muscle, nervous, and connective.3. Organs-Organs are made up of two or more tissues that work together to do a specific job.Example: a heart is an organ made of all four tissues. a large musical instrument having rows of tuned pipes sounded by compressed air, and played using one or more keyboards to produce a wide range of musical effects. 4. Organ Systems-An organ system is a group of organs working together to perform particular jobs.Example: Human organ systems include circulatory, reproductive, digestive, nervous, respiratory. Plant organ system-roots, stems,leaves= transport system.5. Organisms-Sum of all cells, tissues, organs and organ systems makes an organism.An organisms is made when a group of organ systems work together.bacteria, humans, dogs.