Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?

Assertion : Secondary succession takes place in a recently denuded area.
Reason : It is caused due to the baring of an area.

What type of food chain is the following?
Grass $\rightarrow$ Goat $\rightarrow$ Human

In hydrarch succession,the reed swamp stage is preceded by

Organisms that consume milk and curd can be classified as ........

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.