Welcome to 21st National & 9th International Congress on Biology, Semnan, Iran The Iranian Biology Society and Semnan University are honored to announce the 21st National and 9th International Congress on Biology to be held from 16th to 18th February 2021 in Semnan, Iran. The main aim of this event is to present frontline bioscience that help to save the global from sever threats. As well as, we aimed to enable young scientists and students to meet peers from around the world and learn about developing scientific initiatives used worldwide. It also provides a premier interdisciplinary platform to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the fields of biology. The advent of “integrative biology” has revolutionized biology particularly in the medicine and agriculture. The congress consists of four conferences in Biology (Plant Biology; Animal Biology; Cell and Molecular Biology; and Conservation and Environmental Biology). Highlight events include a special panel on Covid-19: Molecular and Cell approaches and workshops to provide practical guidance for young biologists.