Assertion (A): Alveoli contain an extensive  network of blood vessels.  

Reason (R): Alveoli is the site where exchange of  gases occurs.  




  • The alveoli of lungs are richly supplied with blood
  •  Alveoli are the sites where exchange of gases (O 2 and CO 2 ) occurs between blood and the atmosphere. 
  • The alveoli increase the surface area for this exchange of gases and hence have an extensive network of blood vessels to maximise efficiency.



  • The assertion is True
  • The reason is True

The reason is the correct explanation of the assertion

Exchange of gases at alveoli-01.jpg

So, the correct option is (a) 

  1. Class 10
  2. Chapter 6 Class 10 - Life Processes (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo