Which group of living organisms given below is a link in the food chain between green plants and a hawk?

Ecological succession on sand is known as:

Match the following columns:

Column-$I$	Column-$II$
$(a)$ Earthworm	$(i)$ Pioneer species
$(b)$ Succession	$(ii)$ Detritivores
$(c)$ Ecosystem service	$(iii)$ Birth rate
$(d)$ Population growth	$(iv)$ Pollination

Consider the following statements concerning food chains.
$A.$ Removal of $80\%$ tigers from an area resulted in greatly increased growth of vegetation.
$B.$ Removal of most of the carnivores resulted in an increased population of deers.
$C.$ The length of food chains is generally limited to $3-4$ trophic levels due to energy loss.
$D.$ The length of food chains may vary from $2$ to $8$ trophic levels.
Which two of the above statements are correct?

Which of the following exhibits scavenging?

Match the following:

Trophic levels	Examples
$A$. First	$a$. Man
$B$. Second	$b$. Wolf
$C$. Third	$c$. Cow
$D$. Fourth	$d$. Phytoplankton