This document discusses cells, tissues, organs, and organ systems. It explains that cells are the basic building blocks of organisms and contain a nucleus, cell membrane, cytoplasm, and vacuole. Plant cells also contain a cell wall and chloroplasts. Cells can specialize to perform different functions. Groups of similar cells that perform the same function form tissues. Organs are made up of different tissues working together, and organ systems are groups of organs that work as a unit, such as the digestive system.

1. Cells, tissues and organs Biology 2011 Miss Teresita Tognetti

11. Quiz