Why is it advised to use iodised salt in our diet?

If salivary amylase is lacking in the saliva,which of the following events in the mouth cavity will be affected?

What will happen if:
$(a)$ Peristaltic movements do not occur all along the oesophagus?
$(b)$ There are no platelets in the blood?
$(c)$ Rings of cartilage are not present in the trachea?

What is lymph? How is the composition of lymph different from blood plasma? What is the direction of its flow? List two functions of the lymphatic system.

Which is the correct sequence of air passage during inhalation?

$(a)$ Name the following:
$(i)$ Organ which stores bile
$(ii)$ Organ which produces bile
$(b)$ Name one enzyme present in pancreatic juice and give its functions.
$(c)$ What are peristaltic movements?