Ribs move downwards and inwards during exhalation as the volume decreases during exhalation.

Trachea is also a kind of windpipe. It is through it that oxygen reaches the lungs.

There are approximately 300 million alveoli present in each lung.

It is the correct option. Shark is a fish and possesses gills for respiration. Tadpoles have gills for respiration in water which after metamorphosis, develop into lungs.

The moistening of the air takes place in nostrils. Nostrils are lined with mucus which moistens the air.

Respiration rate is number of breaths per minute. Normal breathing rate for humans is 12-20 breaths per minute.

Respiration in yeast cells is anaerobic, which yields alcohol as the byproduct.

Oxygen is distributed in the body of cockroaches through network of tubes called trachea.

Mammals respire through lungs. The exchange of gases takes place in lungs.

Limewater turns milky with CO₂. Thus, it is used to test the presence of CO₂ in exhaled air.

Soil should be turned up, i.e. ploughed to increase the availability of oxygen for root respiration.

Earthworm breathes through its moist skin.

The exchange of gases takes place in the alveoli. The walls of the alveoli are surrounded by a network of blood capillaries. Thin walls of alveoli and capillaries allow for O₂ to enter the capillaries and CO₂ to enter the alveoli for exhalation.

Diaphragm controls the breathing movements of the respiratory system. It is a muscular organ which expands and relaxes during inhalation and exhalation, respectively.

Bronchi take the O₂ from trachea to the lungs. They are the first tube of respiratory canal to enter the lungs.