To solve this problem, we need to match the items in the matrix with their appropriate descriptions. Let's analyze each item:$\newline \bullet$a. Earthworm:$\newline$Earthworms are known as detritivores because they feed on dead organic matter and help in decomposing it.$\newline$This matches with (ii) Detritivore.$\newline \bullet$b. Succession:$\newline$Succession refers to the process by which ecosystems develop over time, starting with pioneer species that colonize an area.$\newline$This matches with (i) Pioneer species.$\newline \bullet$c. Ecosystem service:$\newline$Ecosystem services include processes like pollination, which are beneficial to humans and the environment.$\newline$This matches with (iv) Pollination.$\newline \bullet$d. Population growth:$\newline$Population growth is often measured by natality, which is the birth rate within a population.$\newline$This matches with (iii) Natality.$\newline$Now, let's match the items from the matrix:$\newline a \rightarrow ii, b \rightarrow i, c \rightarrow iv, d \rightarrow iii \newline$This corresponds to Option 4.