What does it mean to say that a gene is expressed and how does this process contribute to the functioning of an organism?

When a gene is expressed, it means that the information encoded in the gene is used to make a specific protein or RNA molecule. This process is essential for the functioning of an organism because proteins and RNA molecules carry out various functions in the body, such as building and repairing tissues, regulating chemical reactions, and controlling the expression of other genes. Gene expression is a fundamental process that allows an organism to grow, develop, and respond to its environment.