If a smoker has a low tidal volume why might he feel tired and run down

In the human body fibrinogen is necessary for sealing cuts and stopping the loss of blood. since fibrinogen is made of chains of amino acids it is an example of which type of organic molecule

Which of the following is an oxidation-reduction reaction? (pictured below)

When a person is exercising the body needs to deliver increased amounts of oxygen to the muscles which component of blood ensures that the muscles will receive it