Which one of the following types of organisms occupy more than one trophic level in a pond ecosystem?

Phosphorus of the ocean becomes available to land plants due to:

Which of the following statements is incorrect regarding the phosphorus cycle?

Which one of the following statements is incorrect for secondary succession?

Identify the correct statements from the following:
$(1)$ Succession occurring in dry areas is called xerarch succession.
$(2)$ The stage where plants can survive in open conditions throughout the year is the herb stage.
$(3)$ Ecological succession leads to a decrease in the net primary productivity of the community.
$(4)$ Primary succession takes an average of $1000$ years to complete.

$A$ man-made ecosystem is: