The process of evapo-transpiration and precipitation is known as

Crystalline rocks are a natural source of which biogenetic element?

The order of organisms in an aquatic food chain is:

Read the following statements carefully and answer the question given below:
$(1)$ $NPP = GPP - R$
$(2)$ Productivity of an ecosystem can be measured in $g/m^2/yr$ or $kcal/m^2/day$.
$(3)$ The total amount of energy produced by all producers in an ecosystem is called Gross Primary Productivity $(GPP)$.
$(4)$ The net primary productivity of the oceans is $55$ billion tons.
State the number of correct statements.

In an ecosystem, which of the following statements is true regarding trophic levels?

Identify the basic components of an ecosystem.