The human genome contains around 20,687 protein-coding genes. Different genes or instructions are read at different times in different cells in response to the requirements of our bodies. Each cell contains two sets of genes, one from your mother and one from your father.
Airborne nitrogen is one of the largest sources of pollution affecting the Chesapeake Bay and its tributaries. Excess nitrogen can fuel the growth of algae blooms, which can block sunlight from reaching underwater grasses and create low-oxygen “dead zones” that suffocate marine life.
Viruses don't have cell walls that can be attacked by antibiotics; instead they are surrounded by a protective protein coat. Unlike bacteria, which attack your body's cells from the outside, viruses actually move into, live in and make copies of themselves in your body's cells
the synthesis of organic compounds by bacteria or other living organisms using energy derived from reactions involving inorganic chemicals, typically in the absence of sunlight.
