Bile is an alkaline fluid produced by the liver and stored in the gall bladder.

On which type of food does salivary amylase act in the buccal cavity,and what is the name of the initial product formed due to the action of this enzyme?

$(a)$ Name the following:
$(i)$ Part where air is filtered by fine hair and mucus.
$(ii)$ Part which terminates in balloon-like structures.
$(iii)$ Balloon-like structures where exchange of gases takes place.
$(iv)$ Part which separates the chest cavity from the abdominal cavity.
$(b)$ Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?

Explain the role of bile juice in digesting food.

Design an experiment to demonstrate that sunlight is essential for photosynthesis.

$(a)$ Draw a sectional view of the human heart and label on it Aorta,Pulmonary arteries,Vena cava,Left ventricle.
$(b)$ Why is double circulation of blood necessary in human beings?