Which of the following statements is correct regarding breathing?

Match the partial pressure of carbon dioxide in different parts involved in diffusion in comparison to the atmosphere.

Column-$I$	Column-$II$ ($mm\, Hg$ pressure)
$P$. Atmospheric air	$I$. $40$
$Q$. Tissues	$II$. $45$
$R$. Oxygenated blood	$III$. $0.3$

Select the correct option:
$(1)$ The respiratory rhythm center for breathing regulation is located in the medulla oblongata of the brain.
$(2)$ Each hemoglobin molecule can carry a maximum of $4$ molecules of $O_2$. (Note: The original question mentioned $CO_2$,which is incorrect; hemoglobin primarily transports $O_2$.)

Match Column-$I$ and Column-$II$ with respect to processes involved in respiration with their explanation:

Column-$I$	Column-$II$
$i$. Cellular respiration	$a$. Exchange of gases $O_2$ and $CO_2$ between blood and tissue cells.
$ii$. Breathing	$b$. Physical process of gaseous exchange between atmospheric air and lungs.
$iii$. Internal respiration	$c$. Gaseous exchange between alveolar air and blood capillaries.
$iv$. External respiration	$d$. Food is oxidized and $ATP$ is generated.

Which of the following is not the function of the conducting part of the respiratory system?

Assertion: In mammals,a complex respiratory system has developed.
Reason: Mammalian skin is impermeable to gases.