The antibacterial agent present in tears is:

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.

Process of exchange of $O_{2}$ from the atmosphere with $A$ produced by the cells is called $B$, which is commonly known as $C$. Choose the appropriate options for the blanks $A$, $B$, and $C$ to complete the given $NCERT$ statement.

Define breathing.

Plants do not need specialized respiratory organs because

When we perform physical exercise,the energy demand is: