How many of the following are primary producers in a terrestrial ecosystem?
Herbaceous plants,Algae,Woody plants,Phytoplankton,Aquatic plants

In a food web,hyenas and vultures are:

Which of the following statements are correct regarding a food chain?
$(a)$ If $80\%$ of tigers are removed from an area,the growth of vegetation in that area increases.
$(b)$ If carnivores are removed from an area,the population growth of deer increases.
$(c)$ The length of a food chain is limited to $3$ to $4$ trophic levels because the amount of energy decreases in the ecosystem.
$(d)$ The length of a food chain is usually $2$ to $8$ trophic levels.

Which of the following statements is incorrect?

$A$ food web:

$A$ : During succession,nutrient availability decreases while biomass level increases.
$R$ : $NCP$ (Net Community Productivity) remains same during succession.