Identify $Z$ in the given figure representing the carbon cycle.

Assertion : In tropical rain forests,$O-$ horizon and $A-$ horizon of soil profile are shallow and nutrient-poor.
Reason : Excessive growth of micro-organisms in the soil depletes its organic content.

Which of the following statements are correct?
$(a)$ Energy flow from producers to consumers is unidirectional
$(b)$ Energy pyramid can never be inverted
$(c)$ Transfer of energy follows the $10\%$ law
Choose the correct answer from the options given below:

Organisms that consume milk and curd can be classified as ........

The importance of an ecosystem lies in

Succession on a secondary bare area is known as: