Which is the first enzyme to mix with food in the digestive tract?

In which part of the alimentary canal is food finally digested?

In each of the following situations,what happens to the rate of photosynthesis?
$(a)$ Cloudy days
$(b)$ No rainfall in the area
$(c)$ Good manuring in the area
$(d)$ Stomata get blocked due to dust

Name the glands associated with the digestion of starch in the human digestive tract and mention their role. How is the required $pH$ maintained in the stomach and small intestine?

What causes the movement of food inside the alimentary canal?

Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long? Give reasons for your answer.