Read the following statements with reference to the villi of small intestine.
(i) They have very thin walls.
(ii) They have a network of thin and small blood vessels close to the surface.
(iii) They have small pores through which food can easily pass.
(iv) They are finger-like projections.
Identify those statements which enable the villi to absorb digested food.
A (i), (ii) and (iv)
B (ii), (iii) and (iv)
C (iii) and (iv)
D (i) and (iv)
how does having thin walls help?