Which of the following provide the greatest surface area for gas exchange?
respiratory bronchioles
alveolar sacs
alveoli
alveolar ducts

The correct answer is: alveoli

Respiratory system or respiratory tract is divided into upper and lower tract. Upper respiratory tract includes nose and its cavities, sinuses, pharynx and the part of the larynx. Lower respiratory tract consists of the trachea, bronchi, bronchioles and the alveoli.

Alveoli are the ends of the respiratory tract the smallest units in it. Alveoli are small folded air sacs that are branching off from alveolar ducts and providing an extremely large surface area for the gas exchange. Gas exchange occurs thanks to small blood vessels – capillaries that surround alveoli and it occurs  via the process of diffusion.

cells spend most of their time in interphase

the answer is c. it will give up it's valence electron to the other atom.