Q18 of 60 Page 1

"Energy flow in a food chain is unidirectional." Justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body.

Energy flows in one direction in an ecosystem. It flows from one trophic level to another trophic level inside a food chain. i.e. energy can’t be converted back to its original form in an ecosystem. It can’s also flow back from consumers to producers, it will flow from producers to consumers and is not in reverse direction. So, it is unidirectional only.


More from this chapter

All 60 →
16

Draw a ray diagram to show the path of the refracted ray in each of the following cases:

A ray of light incident on a concave lens is


(i) passing through its optical center.


(ii) parallel to its principal axis.


(iii) directed towards its principal axis

 17

A narrow beam PQ of white light is passing through a glass prism ABC as shows in the diagram.


(i) Write the name and cause of the phenomenon observed.


(ii) Where else in nature is this phenomenon observed?


(iii) Based on this observation, state the conclusion which can be drawn about the constituents of white light.

 19

Elements forming ionic compounds attain noble gas configuration by either gaining or iosing electrons from their outermost shells. Give reason to explain why carbon cannot attain noble gas configuration in this manner to form its compounds. Name the type of bonds formed in ionic compounds and in the compounds formed by carbon. Also give reason why carbon compounds are generally poor conductors of electricity.

 20

(a) Draw a sectional view of human female reproductive system and label the part where

(i) eggs develop.


(ii) fertilisation take place.


(iii) fertilised egg gets implanted....


(b) Describe, in brief, the •changes the uterus undergoes


(i) to receive the zygote.


(ii) if zygote is not formed.