During inspiration the external intercostal muscles ________________ and the ribs move___________________
relax, upwards and outwards
contract, upwards and outwards
relax, downwards and inwards
contract, downwards and inwards
The correct option is B contract, upwards and outwards Inspiration is a process in which air is drawn into the lungs. The external intercostal muscles are muscles present in between the ribs. During inspiration, the external intercostal muscles contract, and the ribs move upwards and outwards. Expiration is a process in which air is drawn out of the lungs. During expiration, the external intercostal muscles relax, and the ribs move downwards and inwards.