Which of these is a characteristic of cool air

Hemoglobin is a proton that carries oxygen around the body what is hemoglobin made from

2polnis which of the following is an advantage of an in vitro experiment?me

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems