Leaves of annual plants obtain $O_2$ through

Select the correct statements from the following regarding gaseous exchange in plants.
$A$. $A$ terrestrial plant has many air spaces between the cells of leaf and root.
$B$. Woody trees have stomata on bark.
$C$. In aerated soil,oxygen dissolved in water enters root tissue by diffusion.
$D$. Vascular bundles provide thin and large surface area for exchange of gases.
$E$. Carbon dioxide and water vapour diffuse into lenticels.

Why do plants not have respiratory organs?

Which of the following statements is correct?

Percentage of $O_2$ present in inhaled air in man is about (in $\%$)

Which of the following statements best summarizes the relationship between respiratory rate and body size in related animals?