What is the mode of nutrition in $Amoeba$ known as?

Is 'nutrition' a necessity for an organism? Discuss.

Bile juice does not contain any digestive enzymes, yet it is essential for digestion. Explain why.

What are the necessary conditions for autotrophic nutrition and what are its byproducts?

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 main organs of the human digestive system. Also, name the associated glands.