When we perform physical exercise,the energy demand is:

Guard cells are surrounded by

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

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/Explain the following terms:
$(1)$ Cellular respiration
$(2)$ Respiratory system

We know that plants are harmed by excess water. However,some plants survive under flooded conditions. How are they able to manage excess water?