The following diagram shows the phosphorus cycle. Identify the producers in it.

In a food chain of a grassland ecosystem,the top consumers are

Give scientific reasons: Even though plants are autotrophic,they cannot live alone.

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:

Arrange the stages of hydrarch succession in the correct sequence.

$A$: Niche becomes general and broader during biotic succession.
$R$: Species diversity increases but organic matter is decreased.