 These systems range from the molecular level (molecular biology, biochemistry, microbiology, pharmacology, protein chemistry, cytology, immunology, neurobiology and neuroscience) to cellular and tissue-based systems (including devices and sensors), to whole macroscopic organisms (plants, animals), and can even range up to entire ecosystems.The average length of study is three to five years, and the completed degree is signified as a bachelor of engineering (B.S.in engineering).