Which is the primary physical barrier in our body?

In beri-beri,

$DPT$ vaccine doses are administered at specific intervals after birth. Identify the correct sequence for the $1^{st}$, $2^{nd}$, and $3^{rd}$ doses of $DPT$ from the following list:
$I$. $6 \; \text{weeks}$ after birth
$II$. $10 \; \text{weeks}$ after birth
$III$. $14 \; \text{weeks}$ after birth
$IV$. $24 \; \text{weeks}$ after birth
$V$. $29 \; \text{weeks}$ after birth

What are pathogens?

Which of the following measures can be taken to prevent diseases spread by mosquitoes?

For effective treatment of the disease,early diagnosis and understanding its pathophysiology is very important. Which of the following molecular diagnostic techniques is very useful for early detection?