3 Why, do you think, does the Punjab have the highest population in the country?

Because

Explanation:

Punjab literally means the land of 5 rivers term refers to the 5 rivers flowing thru the region. Due to its rivers Punjab is the most fertile and most populated province of Pakistan. People speak Punjabi here and have many colorful traditions.  

Punjab is considered most developed, populous, and prosperous province of Pakistan having about 60% of the country's total population living in it.

Punjab has a total population of 30,141,373 as of 2020 that around 3 cr and has a fertility rate of 1.7%. Due to the fertile soils and good climate conditions for cultivation, the area has a large number of agricultural fields that helps people provide their income.

I hope it helped .