The first step in the legislative process is the introduction of a bill to Congress. Anyone can write it, but only members of Congress can introduce legislation. Some important bills are traditionally introduced at the request of the President, such as the annual federal budget. During the legislative process, however, the initial bill can undergo drastic changes. After being introduced, a bill is referred to the appropriate committee for review. There are 17 Senate committees, with 70 subcommittees, and 23 House committees, with 104 subcommittees. The committees are not set in stone, but change in number and form with each new Congress as required for the efficient consideration of legislation. Each committee oversees a specific policy area, and the subcommittees take on more specialized policy areas. For example, the House Committee on Ways and Means includes subcommittees on Social Security and Trade.
The main functions of the respiratory system are to obtain oxygen from the external environment and supply it to the cells and to remove from the body the carbon dioxide produced by cellular metabolism.
